Gene expression profile biomarkers and therapeutic targets for brain aging and age-related cognitive impairment

ABSTRACT

A statistical and functional correlation strategy to identify changes in cellular pathways specifically linked to impaired cognitive function with aging. Analyses using the strategy identified multiple groups of genes expressed in the hippocampi of mammals, where the genes were expressed at different levels for several ages. The aging changes in expression began before mid-life. Many of the genes were involved in specific neuronal and glial pathways with previously unrecognized relationships to aging and/or cognitive decline. The processes identified by the strategy suggest a new hypothesis of brain aging in which initially decreased neuronal activity and/or oxidative metabolism trigger separate but parallel genomic cascades in neurons and glia. In neurons, the cascade results in elevations in calcium signaling and reductions of immediate early gene signaling, biosynthesis, synaptogenesis and neurite remodeling. In contrast, glia undergo increased lipid metabolism and mediate a cycle of demyelination and remyelination that induces antigen presentation, inflammation, oxidative stress and extracellular restructuring. These identified genes and the proteins they encode can be used as novel biomarkers of brain aging and as targets for developing treatment methods against age-related cognitive decline, Alzheimer&#39;s Disease and Parkinson&#39;s Disease.

STATEMENT OF GOVERNMENT INTEREST

This invention has been made in part with government support under grants AG04542, AG10836, AG18228 and AG14979 from the National Institute on Aging, and by MH59891. The government of the United States of America may have certain rights in this invention.

FIELD OF THE INVENTION

The invention relates generally to genetic algorithms, and more particularly to the identification of gene expression profile biomarkers and therapeutic targets for brain aging.

BACKGROUND OF THE INVENTION

Brain aging processes are enormously complex phenomena that affect multiple systems, cell types and pathways, and result in cognitive decline and increased risk of Alzheimer's disease (AD). Landfield P W et al., J Neurobiol 23: 1247-1260 (1992). Although several biological mechanisms have been putatively linked to brain aging or Alzheimer's disease, including inflammation, oxidative stress, Ca²⁺ dyshomeostasis (Landfield, P W & Pitler T A, Science 226: 1089-1092 (1984); Landfield P W et al., J Neurobiol 23: 1247-1260 (1992)), mitochondrial dysfunction and chronic exposure to adrenal stress hormones (Landfield P W et al., Science 214: 581-584 (1981); Porter N M & Landfield P W, Nature Neurosci 1: 3-4 (1998)), the specific mechanisms and pathways, if any, through which they are linked to impaired brain function are not understood.

It is widely thought that gene expression changes contribute to many aspects of declining function with aging. Finch C E, Longevity, Senescence and the Genome, 37-42 (Univ. Chicago Press, Chicago, 1990). It is also thought that gene expression changes are important for processing and storage of memory. However, not all genes that change expression in the brain with aging are thought to be important for cognition.

Gene-expression changes that specifically contribute to age-related memory decline should selectively change with brain aging and should be correlated specifically with measures of age-associated cognitive decline; that is, a subset of the full set of aging-dependent genes should also correlate with age-related cognitive decline. See, Lockhart D J & Barlow C, Nat Rev Neurosci 2: 63-68 (2001) and Mimics K, Nat Rev Neurosci 2: 444-447 (2001).

If a subset of age-dependent genes also shows expression patterns directly correlated with age-related memory decline, then such a subset of “aging and cognition-related genes” (ACGs) would be extremely helpful as biological indexes (“biomarkers”) for assessing or diagnosing the degree of age-related cognitive impairment in individual subjects. In turn, the ability to measure aging-related cognitive impairment quantitatively is essential for discovering new therapeutic targets, and developing new strategies and pharmaceutical compounds for counteracting normal age-related cognitive decline and/or age-related neurodegenerative diseases, including Alzheimer's disease (AD) or Parkinson's disease (PD).

Identifying ACGs in any mammalian species therefore, might have great therapeutic usefulness. Moreover, because of the well-established homologies of most genes across mammalian species and because of the clear similarities in patterns of brain aging and cognitive decline across species, identification in any mammal would have human health implications. Furthermore, because the primary risk factor for Alzheimer's disease and Parkinson's disease is aging itself, therapeutic approaches developed for aging-related cognitive impairment should also help ameliorate cognitive decline from age-related neurodegenerative disease. Thus, there is a clear need for identifying ACGs but, to date, such genes have not been discovered for any mammal.

Gene microarray technology provides a powerful approach for unraveling the complex processes of aging. To date, however, its impact has been limited by statistical problems, small sample sizes, and difficulty in assessing functional relevance. Moreover, studies that have examined gene expression during brain aging using microarrays have not used sample sizes large enough to provide adequate statistical power for formal statistical testing. Lee C K et al., Nature Genetics 25: 294-297 (2000); Jiang C H et al., Proc Natl Acad Sci USA 98: 1930-1934 (2001) Therefore, even the genes they have reported to change with aging have not been validated by accepted statistical criteria.

The extremely large data sets generated by microarrays pose formidable bioinformatics and resource problems that have to date limited the impact of this powerful technology. Because of these difficulties, most microarray studies have relied on simple fold change comparisons in small samples. However, neither fold change analyses nor the small sample protocols widely used allow the direct estimates of variance necessary for defining type I error (false positives). In addition, fold change criteria, by definition, select for large changes. Therefore, they exhibit low detection sensitivity (high false negatives, or type II error), and are unable to identify the modest changes that often characterize functionally important (and, therefore, tightly regulated) genes. The inability to assign type I error is a particularly critical problem for microarray studies because the thousands of comparisons of gene expression in such analyses greatly increase the expected false positives. For example, even if group sizes were sufficient for formal statistical analyses, and 5000 gene transcripts were each tested by t-test for differences between two conditions at p≦0.05, the false positive rate is equal to the p-value and, consequently, 5% of the 5000 tested transcripts (250) would be expected to be found significant by chance alone.

Although microarray studies have some important offsetting advantages that improve statistical confidence (e.g., co-regulation of genes within a functional group), there is increasing recognition that microarray experiments should generally meet the same statistical standards as other biological experiments or, at least, should systematically estimate the degree of statistical uncertainty. Several strategies to improve statistical confidence have been developed for small-sample microarray studies, but these generally rely on indirect estimates of variance and/or greatly sacrifice sensitivity (i.e., stringent p-values).

Another highly important problem of microarray studies is that of determining which of the hundreds of expression changes that may be observed are likely to be functionally relevant. Correlation analysis is one quantitative approach to linking gene expression with function, although it also requires relatively large sets of independent samples. Expression-function correlations fulfill a key prediction of a causal relationship (i.e., that causally related variables should co-vary) and therefore, can serve as a valuable tool for the identification of candidate functionally relevant genes. Nonetheless, there have been few correlation studies attempting to link cognitive dysfunction with univariate gene expression patterns across individual subjects, much less using the massive amounts of data generated in microarray analyses.

SUMMARY OF THE INVENTION

The invention provides a statistical and functional correlation strategy to identify changes in cellular pathways specifically linked to impaired cognitive function with aging. The bioinformatics and functional correlation strategy improves the power of microarray analyses and provides the ability to test whether alterations in specific hippocampal pathways are correlated with aging-related cognitive impairment. The invention is useful for application in large, well-powered groups and for controlling type I error (false positives), enhancing detection sensitivity (reducing type II false negatives) and determining which aging changes in expression are most closely correlated with declining brain function.

Accordingly, the invention provides a method for identifying a biomarker for brain aging, where the biomarker is a polynucleotide or a polypeptide encoded by said polynucleotide. The method involves first obtaining a set of polynucleotides obtained from a set of brain samples (such as hippocampal samples), where the members of the set of brain samples were obtained from members of a set of mammals, wherein the set of mammals contains more than two members, with at least young, mid-aged and aged members, and then identifying the identity and amount of the members of the set of polynucleotides present in the brain samples. The method then involves the steps of deleting certain non-biomarker polynucleotides from the set of polynucleotides, testing by a conventional statistical method (such as) for a significant effect of aging across the young, mid-aged and aged members; and correlating the identity and amount of the members of the set of polynucleotides present in the brain samples with cognitive performance in behavioral tests.

By use of the methods of the invention, one skilled in the genomics art can identify multiple groups of related genes, many representing processes with previously unrecognized relationships to aging and/or cognitive dysfunction. Thus, the invention also provides compositions of matter comprising sets of genes, expressed sequence tags (ESTs), polynucleotides and polypeptides encoded by said polynucleotides identified as being involved in the aging processes. These sets usefully result in a statistically validated, comprehensive overview of mammalian, including human, functional brain aging. In particular, the set of genes can be used for the diagnosis of human age-related disease, such as an age-related neurodegenerative condition, including Alzheimer's disease or Parkinson disease.

The invention provides a set of biomarkers for brain aging, where (a) the set of biomarkers comprises at least two members; (b) the brain expression patterns of the members of the set are significantly altered with aging as determined by a conventional statistical method (such as ANOVA or student's t test), with p<0.05; (c) the brain expression patterns of the members of the set are correlated (using a conventional statistical correlation test, e.g., tested by Pearson's or Spearman's correlation test) across age groups with cognitive performance in behavioral tests, with a correlation of p<0.05 (or with a more stringent correlation of p<0.01 or p<0.001) between brain expression and cognitive performance; and (d) the cognitive performance in behavioral tests significantly altered with aging as determined by a conventional statistical method. The biomarkers may also correlate with a behavioral measure of functional impairment, such as an age-related neurodegenerative condition, including Alzheimer's disease or Parkinson's disease.

The invention also provides a set of at least two biomarkers for brain aging, where where the brain expression patterns of the members of the set are significantly altered with aging as measured by a conventional statistical correlation test at a significance level of p<0.01.

The invention further provides a set of at least two biomarkers for brain aging, where the brain expression patterns of the members of the set are significantly altered with aging as determined by a conventional statistical method, with p<0.05 (or a more stringent correlation, such as p<0.025, p<0.01 or p<0.001).

In one example of the invention, rats in three age groups (Young, Mid-Aged, Aged) were characterized on two memory tasks and each mammal's hippocampal CA1 region was analyzed by a microarray analysis for gene expression. These analyses identified multiple groups of genes, many representing pathways with previously unrecognized relationships to aging and/or cognitive decline. The analysis showed that for all groups, the aging changes in expression began by mid-life.

In one aspect of the invention, the known interactions of the identified processes suggest an integrative model of specific cellular cascades that begin in mid-life and eventually impair cognitive function and increase neuronal vulnerability. Initially decreased neuronal activity and/or oxidative metabolism trigger separate but parallel genomic cascades in neurons and glia. In neurons, the cascade results in reductions of immediate early gene signaling, biosynthesis, synaptogenesis and neurite remodeling. In contrast, glia undergo increased lipid metabolism and mediate a cycle of demyelination and remyelination that induces antigen presentation, inflammation, oxidative stress and extracellular restructuring. Intervention studies based on these findings can identify the cause and effect interactions among the complex processes of brain aging.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a set of bar graphs showing age-dependent impairment of memory performance. Male Fischer 344 rats aged 4 months (Young, n=10), 13 months (Mid-Aged, n=10) and 24 months (Aged, n=10) were used. Aged animals exhibited significantly reduced performance on 24 hr memory retention on both the Morris spatial water maze task (SWM; FIG. 1A) and object memory task (OMT; FIG. 1B) in comparison to either Young or Mid-Aged animals (*p<0.05, **p<0.01, by 1-way ANOVA and Tukey's post-hoc). As shown in the bar graph, the Young and Mid-Aged animals did not differ significantly from each on either the SWM or OMT task. On the SWM task (FIG. 1A), higher platform crossings reflects greater retention of the spot where the platform was previously located. For the OMT (FIG. 1B), a higher memory index reflects greater retention of the previously explored object, and resultant increased exploration of the novel object.

FIG. 2 is a flow chart for a filtering and statistical test algorithm for identifying primary set of ACGs. The flow chart also includes the results for an example of the invention. An initial set of 8,799 transcript sets contained on the U34A Gene Chip (see, EXAMPLE 2) was filtered prior to statistical testing, to reduce expected false positives. Probe sets were removed if they were called “absent” (1a.), if they were unknown expressed sequence tags (ESTs) (1b.) or if the difference between the Young and Aged groups did not comprise at least 75% of the maximal normalized age differences (1c.). Each of the remaining 1,985 transcript (gene) sets was then tested by ANOVA across the three age groups (n=9-10) to determine if it changed significantly with aging (2.). Each of the 233 genes that changed significantly with age (p≦0.025) was then tested across all animals (n=29) for significant behavioral correlation with OMT, SWM, or both SWM and OMT (Pearson's; 3a). Furthermore, of the genes that did not correlate with behavior, ones that showed an ANOVA p value≦0.001 were also retained for further analysis (3b). In total, 172 genes were considered, 161 of which could be considered ACGs.

FIG. 3 is a set of line graphs showing correlation of gene expression and OMT across individual animals. Behavioral correlation is measured across all age groups. For genes that decreased with aging, the five best positive correlations (A) and for genes that increased with aging, the five best negative correlations (B) are shown (see Legend: correlation p-values in parentheses). Standardized values for both expression and OMT performance are shown on the Y-axis. The animals were ranked for OMT performance on the X-axis, from worst (1) to best (29), and OMT performance was plotted as a heavy black line on both A and B for the purposes of comparison. Genes involved in early responses and synaptic remodeling were among the five most highly correlated genes that decreased with aging, whereas those related to actin assembly and inflammation were among the five most highly correlated genes that increased with aging.

FIG. 4 is a line graph and pie chart insert showing functional categories and age course of genes decreased with aging. Chronological patterns are shown for aging changes for five of the eight functional categories (some categories were omitted to improve legibility and because they were highly similar to the ones already depicted). Each gene's expression was normalized prior to calculating category mean values. Note that most down-regulated categories exhibited ≧50% of mean changes by the Mid-Aged point, and showed relatively less change between the Mid-Aged and Aged animals. No category showed a predominantly Mid-to-Aged pattern of change. The pie-chart insert shows proportion of genes that followed each of the three possible routes to decreased expression with aging.

FIG. 5 is a line graph and pie chart insert showing functional categories and age course of genes increased with aging. Chronological patterns are shown for aging changes for five of the eleven functional categories of behaviorally-correlated upregulated genes (some categories were omitted to increase legibility and because their pattern of change with age was highly similar to that of categories already depicted). Calculations and nomenclature as in FIG. 4. Note that, in contrast to the majority of downregulated genes (FIG. 4), changes in upregulated categories did not tend to level off after mid-life but instead showed continuing change between mid-life and late-life (e.g., a monotonic pattern). Similar patterns were seen when all upregulated genes are considered (Pie-chart inset).

FIG. 6 is a micrograph showing a model of parallel neuronal and glial cascades leading to functional impairment. Early in mid-life, initiating factors (e.g., reduced neuronal activity, onset of late-acting gene expression) induce downregulation of neuronal (N) oxidative phosphorylation triggering a cascade of impaired IEG signalling, biosynthetic potential, and critically, decreased capacity for neurite remodeling and synaptogenesis. In parallel, enhanced lipid metabolism and demyelination are triggered in oligodendrocytes (O) by altered energy metabolism or neural activity. In turn, astrocytes (A) hypertrophy and increase glycolysis of the glucose taken up by astrocytic endfeet on capillaries (C). Simultaneously, phagocytosis of myelin fragments triggers oxidative damage and inflammatory responses in microglia (M). Eventually, the combined effects of reduced synaptic remodeling, decreased activity and axon conduction, altered extracellular matrix and expanding inflammation result in cognitive failure and neuronal vulnerability.

DETAILED DESCRIPTION OF THE INVENTION

The concept of “biomarker” is well-known and useful concept for those of skill in the genomic art. In general, a biomarker is a measurable biological manifestation that is a quantitative indication of the presence and degree of an underlying biological process of interest.

We have devised a multi-stage method for the identification of biomarkers for brain aging, using gene expression microarrays and behavioral testing. The method of the invention allows one skilled in the genomics art to identify both “aging and cognition-related genes” (ACGs) and unique genes that change with brain aging alone, based on formal statistical testing.

As used in this specification, the word “cognitive” is defined as comprising the higher order intellectual/brain processes involved in learning, including attention, acquisition, short-term memory, long-term memory and memory retrieval, among others.

As used in this specification, across different mammalian species, age definitions are as follows: “Young” mammals are those at or beyond reproductive maturity for the species. “Mid-aged” is defined in two ways: at or around half the average lifespan for the species and at or around the midpoint between reproductive maturity and average lifespan. “Aged” mammals are those at or around average lifespan. Animals intermediate between two ages could be considered as part of the group to which they are most closely chronologically related (with the exception of young animals, for whom it would be inappropriate to include prepubescent individuals).

We used the bioinformatics and functional correlation strategy of the invention for microarray analyses. As a result, we were able to detect multiple groups of related genes that were altered by brain aging and also correlated with cognitive function across individual subjects. Most of the shifts in genomic regulation began by mid-life, well before the onset of measurable cognitive impairment, implying that cognitive function is not altered substantially without further progression and/or the cumulative effects of the initial changes in gene regulation.

This analysis depended on a novel combination of three approaches for microarray research: (a) the quantitative measurement of the dependent function of interest (cognitive performance), which provided a basis for large-scale expression-function correlation analyses; (b) the application of formal statistical analyses (ANOVA, Pearson's) to large groups of independent microarray samples, which conferred substantial statistical power and high detection sensitivity for even modest changes (low false negative type II error); and c) systematic estimates of the maximum probabilities of false positives in our data. Our results using the method of the invention provide a generally comprehensive overview of hippocampal genes/processes that are altered with brain aging and closely linked to brain functional decline.

To verify the method of the invention, we first tested young (3-4 months old), mid-aged (12-13 months old) and aged (24-25 months old) rats (n=9-10 per group) for performance on the Morris spatial water maze (SWM) and object memory task (OMT). Both behavioral tests clearly and reliably (statistically) revealed aging-related cognitive impairment (FIG. 1).

We then anesthetized (for euthanasia) all animals and dissected out a region of the brain (CA1 region of the hippocampus) known to be important for memory. These brain tissues were then prepared for analyses of gene expression profiles (mRNA content) on Affymetrix GeneChip microarrays specific for the rat genome (RG-U34A arrays) (one array for each individual rat sample). The microarrays were then read and analyzed for expression profile data on an Affymetrix GeneChip System according to the manufacturer's instructions.

The behavioral and microarray methods that were used can reasonably be expected to apply as well to mice as to rats. Similar behavioral and microarray methods known to those of skill in the art can be used for testing of other mammals, including humans. The utility of the method of the invention for human testing is discussed below.

We then transferred the data into standard computer spreadsheets (e.g., Excel) for performing statistical analyses of the effects of aging. Using Analysis of Variance (ANOVA) we defined the set of genes whose degree of expression changed significantly with brain aging. We then used that set of “Aging Genes” and tested each gene's expression profile (across only the aged animals) for significant correlation with memory performance on the Object Memory Task (OMT) as well as the Morris spatial water maze (SWM). The “Aging Genes” whose expression patterns correlated significantly with cognitive performance were defined as the primary subset of “Aging and Cognition-Related Genes” (ACGs), and subcategorized as OMT-associated, SWM-associated, or both OMT and SWM-associated. We further included genes with no behavioral association that had an ANOVA p value≦0.001 since genes identified at this more stringent level are less subject to the error of multiple testing (FIG. 2, TABLES 1A and 1B).

Based on those large-scale studies, we have developed a list of ACGs that appear to have considerable potential importance for assessing and generating new treatments for age-dependent functional decline (TABLES 1A and 1B).

These lists contain some genes that were identified previously as being linked to brain aging or neurodegeneration (e.g., inflammation or mitochondrial genes, Lee C K et al., Nature Genetics 25: 294-297 (2000)) but none has been previously shown to be specifically associated with both brain aging and aging-dependent cognitive impairment. Further, many genes on our list have not even been shown previously to be linked to brain aging alone or to cognition alone. Thus, our lists of ACGs are unique and useful biomarkers and therapeutic targets specifically for aging-dependent cognitive impairment. In addition, our list of all genes that change with brain aging contains many genes never before reported to change with brain aging, and therefore provides a useful and unique panel of gene biomarkers and therapeutic targets for study and treatment of brain aging.

In addition to these lists for identified genes, we have also performed the same analyses and compiled the same lists for unidentified expressed sequence tags (ESTs) that are on the same Affymetrix Chips (TABLE 2). These are valuable data, because once the ESTs are identified, they can provide therapeutic targets.

Using the method of the invention, we were able to identify a number of processes and pathways that previously have not been clearly associated with normal brain aging. The most unexpected findings included altered expression profiles suggestive of increased myelin and lipid turnover, as well as widespread changes indicating coordinated downregulation of oxidative metabolism, decreased neurite outgrowth and synaptogenesis. Other novel genes we identified appear to suggest alterations in general metabolic and biosynthetic chaperone functions. In addition, many of the identified groups confirmed previously described changes in expression for genes regulating several major processes (e.g., inflammation, glial reactivity, oxidative stress). However, our results also extend the earlier findings considerably by revealing the extent of the changes and the concurrent upregulation of potentially orchestrating transcription factors and cytokines that may provide important clues to pathogenic mechanisms.

In order to begin to develop an integrative overview of potential interactions among the multiple altered expression patterns observed here, we considered functional implications at the pathway level. Our interpretations rely on the functions that have been previously associated with many of the genes identified by those of skill in the genomics art. These are identified through PubMed literature searches, annotations provided by Affymetrix, entries in the SwissProtein database <http://www.expasy.ch/sprot/sprot-top.html> and associations reported in the Genome Ontology (GO; <http://www.geneontology.org>). We also rely on the general assumption held by those of skill in the genomics art that similar changes in the expression of multiple genes of a particular pathway imply like changes in the functions mediated by the encoded proteins of that pathway. Gene expression changes also can reflect compensatory negative feedback regulation (or other dissociations of gene expression and protein function), but the potential confound of dissociation is presumably less of a problem in microarray analyses in which multiple genes in a pathway are observed to change in the same direction. Some of the primary metabolic pathways and processes considered in the interpretations are depicted in TABLE 1.

Functional Groups. We found age-dependent upregulation of many ACGs involved in inflammatory/immune/stress responses and downregulation of many involved in energy metabolism. In addition, we found alterations of gene expression reflecting multiple categories/pathways not previously recognized to change with normal aging. These included upregulation of genes for myelin proteins, cholesterol biosynthesis and transport, amino acid metabolism, intracellular Ca²⁺ signaling, and protein processing, as strongly suggesting an ongoing cycle of remyelination and demyelination. We also found widespread downregulation of genes for biosynthesis, immediate early responses, and synaptic structural plasticity, suggestive of neuronal involution. Multiple transcriptional regulators and cytokines were also identified that may play orchestrating roles. Nearly all expression changes began by mid-life but cognition was not impaired until late life. Upregulated genes for inflammation and intracellular Ca²⁺ release were among those most closely correlated with impairment. TABLE 1A Functionally Grouped ACGs and Genes Showing Highly Significant Age-Dependent Decreases in Expression GenBank Description Young Mid Age ANOVA p behall Synaptic Structural Plasticity M64780* Agrn, Agrin 2746 ± 105 2334 ± 74  2207 ± 79  0.0005 Both L21192 GAP-43, membrane attached signal protein 2 (brain) 10324 ± 546  8990 ± 327 8165 ± 480 0.0095 Both S82649 Narp, neuronal activity-regulated pentraxin 4358 ± 300 3470 ± 143 3247 ± 185 0.0029 OMT M74223 VGF, neurosecretory protein 6697 ± 373 5836 ± 387 4722 ± 369 0.0042 OMT U63740* Fez1, Protein kinase C-binding protein Zeta1 10339 ± 180  9322 ± 258 9388 ± 330 0.0239 OMT AB003726 Homer1a, RuvB-like protein 1 3546 ± 270 2354 ± 121 2469 ± 132 0.0001 None U19866 Arc, activity-regulated cytoskeleton-associated protein 6374 ± 527 4408 ± 228 4094 ± 398 0.0008 None Transcription Regulator M18416 Egr1, Early growth response 1 (Krox-24) 4911 ± 259 3688 ± 177 3544 ± 165 0.0001 Both M92433 NGFI-C, Zinc-finger transcription factor 2037 ± 149 1576 ± 44  1495 ± 70  0.0009 Both L08595 Nuclear receptor subfamily 4, group A, member 2 1467 ± 80  1186 ± 83  1011 ± 62  0.0010 Both AI030089 Nopp130, nucleolar phosphoprotein p130 471 ± 31 397 ± 31 314 ± 22 0.0022 Both AF016387 RXRG, retinoid X-receptor gamma 1900 ± 129 1503 ± 95  1365 ± 103 0.0059 Both AA800794 HT2A, zinc-finger protein 2480 ± 67  2396 ± 41  2097 ± 73  0.0004 OMT AA799641 S164, Contains a PWI domain associated with RNA splicing 7645 ± 169 7690 ± 183 6842 ± 250 0.0106 OMT U78102 Egr2, Early growth response 2 576 ± 95 223 ± 21 205 ± 23 0.0001 SWM U44948 SmLIM, smooth muscle cell LIM protein 1166 ± 15  928 ± 55 887 ± 38 0.0001 SWM AA891717 USF-1, upstream stimulatory factor 1 3607 ± 142 2993 ± 91  3025 ± 66  0.0003 None AF095576 Aps, adaptor protein with pleckstrin and src homology 526 ± 40 275 ± 49 272 ± 46 0.0007 None Intracellular Signal Transduction AI176689 MAPKK 6, mitogen-activated protein kinase kinase 6 2012 ± 84  1781 ± 92  1528 ± 88  0.0030 Both X89703 TPCR19, Testis Polymerase Chain Reaction product 19 361 ± 25 320 ± 25 252 ± 24 0.0155 Both L04485 MAPPK1, mitogen-activated protein kinase kinase 1 13110 ± 365  11951 ± 312  11200 ± 506  0.0104 OMT AA817892 Gnb2, Guanine nucleotide binding protein (beta 2 6500 ± 159 5606 ± 214 5765 ± 218 0.0110 OMT subunit) AF000901 P58/P45, Nucleoporin p58 597 ± 43 444 ± 51 391 ± 47 0.0150 OMT M87854 Beta-ARK-1, beta adrenergic receptor kinase 1 1994 ± 110 1723 ± 90  1544 ± 114 0.0202 OMT AF058795 Gb2, GABA-B receptor 9443 ± 360 9064 ± 478 7857 ± 323 0.0228 OMT AA800517 VAP1, vesicle associated protein 637 ± 72 674 ± 61 455 ± 35 0.0228 OMT Signal Transduction AF003904 CRH-binding protein 773 ± 51 782 ± 35 630 ± 23 0.0119 Both M15191 Tac1, Tachykinin 1415 ± 110 1078 ± 57  1068 ± 74  0.0093 OMT AF091563 Olfactory receptor 440 ± 21 367 ± 29 332 ± 27 0.0233 SWM M64376 Olfactory protein 810 ± 26 605 ± 83 568 ± 57 0.0247 SWM M15880 Npy, Neuropeptide Y 4647 ± 158 3561 ± 223 3668 ± 141 0.0004 None Adhesion, Extracellular Matrix M27207 Col1a1, Procollagen-type I (alpha 1) 678 ± 24 521 ± 43 480 ± 23 0.0005 Both AF104362 Omd, Osteomodulin (osteoadherin) 289 ± 16 217 ± 24 185 ± 15 0.0024 Both D63886 MMP16, matrix metalloproteinase 16 664 ± 23 604 ± 37 542 ± 19 0.0180 Both M21354 Col3a1, collagen type III alpha-1 203 ± 22 157 ± 13 132 ± 9  0.0120 SWM AB010437 CDH8, Cadherin-8 163 ± 24 100 ± 12  83 ± 17 0.0128 SWM Metabolism L03294 Lp1, lipoprotein lipase 1147 ± 69  918 ± 40 749 ± 37 0.0000 Both S68245 Ca4, carbonic anhydrase 4 2272 ± 75  1993 ± 63  1825 ± 54  0.0002 Both AA859975 LOC64201, 2-oxoglutarate carrier 4792 ± 68  4370 ± 102 4255 ± 97  0.0010 Both M24542 RISP, Rieske iron-sulfur protein 10337 ± 308  9095 ± 327 8833 ± 128 0.0013 Both M18467 Got2, glutamate oxaloacetate transaminase 2 9470 ± 241 8355 ± 179 8332 ± 322 0.0061 Both X64401 Cyp3a3, Cytochrome P450- subfamily IIIA 805 ± 64 762 ± 51 581 ± 34 0.0089 Both (polypeptide 3) U83880 glycerol-3-phosphate dehydrogenase, mitochondrial 2054 ± 73  1988 ± 77  1673 ± 111 0.0127 Both J05499 GLS, glutaminase (mitochondrial) 915 ± 24 844 ± 44 787 ± 14 0.0238 Both U90887 Arg2, arginase type II 499 ± 21 374 ± 31 364 ± 22 0.0015 OMT M22756 Ndufv2, mitochondrial NADH dehydrogenase (24 kDa) 12293 ± 574  10193 ± 670  9260 ± 750 0.0134 SWM Transporters, Carriers L46873 Slc15a1, Oligopeptide transporter 426 ± 30 411 ± 24 292 ± 27 0.0028 Both AB000280 PHT1, peptide/histidine transporter 802 ± 20 659 ± 40 691 ± 37 0.0198 OMT U87627 MCT3, putative monocarboxylate transporter 687 ± 33 521 ± 22 480 ± 38 0.0002 SWM AA799389 Rab3B, ras-related protein 353 ± 21 324 ± 25 251 ± 23 0.0150 SWM Growth, Biosynthesis, Maintenance X16554 Prps1, Phosphoribosyl pyrophosphate synthetase 1 3159 ± 81  2747 ± 74  2637 ± 97  0.0006 Both U66470 rCGR11, Cell growth regulator 820 ± 31 676 ± 31 662 ± 38 0.0051 Both M37584 H2AZ, H2A histone family (member Z) 5335 ± 73  4906 ± 186 4600 ± 162 0.0090 Both U90610 Cxcr4, CXC chemokine receptor 811 ± 56 812 ± 59 614 ± 29 0.0109 Both AA874794 Bex3, brain expressed X-linked 3 16735 ± 376  14986 ± 588  14238 ± 457  0.0047 OMT AA892506 coronin, actin binding protein 1A 4101 ± 121 3625 ± 114 3558 ± 135 0.0104 OMT AA893939* DSS1, deleted in split hand/split foot protein 1 4201 ± 76  3860 ± 129 3658 ± 141 0.0149 OMT AF087037 Btg3, B-cell translocation gene 3 652 ± 55 676 ± 71 460 ± 29 0.0163 OMT U06099 Prdx2, Peroxiredoxin 2 12667 ± 675  11742 ± 641  10339 ± 272  0.0216 OMT AI172476 Tieg-1, TGF-beta-inducible early growth response 1127 ± 99  925 ± 63 812 ± 53 0.0177 SWM protein 1 AA866411 Necdin, neuronal growth suppressor 1994 ± 81  1568 ± 86  1542 ± 62  0.0005 None Protein Processing and Trafficking X54793 Hsp60, heat shock protein 60 10088 ± 333  9602 ± 299 8693 ± 229 0.0071 Both AA875047 TCPZ, T-complex protein 1 (zeta subunit)  997 ± 161 728 ± 99 470 ± 59 0.0095 Both D21799 Psmb2, Proteasome subunit (beta type 2) 7298 ± 242 6892 ± 229 6395 ± 177 0.0241 Both U53922 Hsj2, DnaJ-like protein (RDJ1) 10716 ± 382  8836 ± 190 8392 ± 204 0.0000 SWM X78605 rab4b, ras-homologous GTPase 3131 ± 292 2040 ± 196 2006 ± 135 0.0012 None

For TABLE 1A, “GenBank” is the gene accession number established at the web accessible GenBank database <http://www.ncbi.nlm.nih.gov/>, The “Description” includes a ‘common name’ (if applicable) as well as a brief description of the gene product. Values for Young, Mid-Aged, and Aged categories are the mean±SEM of expression values. Genes are put into functional categories (see, above) and grouped by their level of association with behavior (expression correlated significantly (Pearson's; p≦0.025) with both tasks, with the OMT, with the SWM, or with none of the tasks but highly significant across age (p≦0.001 on ANOVA across age, p>0.025 for correlation on both SWM and OMT). Within each level of association, genes are ranked by the significance of the age-dependent change in their expression level (ANOVA; p≦0.025). Asterisked (*) genes are those that also showed a significant behavioral correlation (Pearson; p≦0.025).

ACGs that were downregulated with aging (TABLE 1A) appeared primarily to represent metabolic and neuronal functions (FIG. 3 a).

Metabolism. Multiple genes related to functions of the mitochondrial electron transport chain (e.g., glycerol 3-phosphate dehdrogenase, NADH dehydrogenase, Rieske's iron-sulpher protein) were downregulated with aging (TABLE 1A). Moreover, we found aging-dependent downregulation of several genes related to pathways important for glucogenic amino acid catabolism, including glutaminase and arginase (TABLE 1A).

Synaptic Structural Plasticity. One of the most prominent categories of identified genes showing decreased expression and behavioral correlation was that comprising genes involved in synaptic structural plasticity, including neurite outgrowth and synaptogenesis (e.g., decreased expression of genes encoding agrin, GAP-43, Homer 1a, Narp, Arc, etc.) (TABLE 1A). Many of these genes are activity-dependent in neurons and have been linked previously to synaptic plasticity, neurite remodeling or learning in univariate studies (e.g., Biewenga J E et al., Acta Biochim Pol 43: 327-38 (1996); Steward O et al., Neuron 21: 741-51 (1998), Mantych K B & Ferreira A, J Neurosci 21: 6802-9 (2001), Guzowski J F et al., J Neurosci 20: 3993-4001 (2000), Bezakova G, et al. Proc Natl Acad Sci USA 98 9924-9 (2001)), although Gap-43 is one of the few reported so far to change with aging. Similarly, many other neural activity-dependent genes, including IEGs in the Transcription Regulators and Signaling categories (e.g., Egr1, Egr 2, MAPKK, etc.), showed decreased expression with aging and were correlated with impaired cognition (TABLE 1A).

In addition, multiple genes important for general growth and biosynthetic mechanisms, chaperone functions and protein processing were also downregulated with aging (e.g., hsp60, histone H2AZ, proteasome subunit, DNA J-like homolog, etc.) as were specific neuronal signaling genes (e.g., GluR 5-2, the kainate receptor; and neuropeptide Y) (TABLE 1A). These widely downregulated biosynthetic and signaling genes appear to reflect a general involution of metabolic and neurite structural remodeling processes in neurons (e.g., FIG. 4, TABLE 1A). Chaperone proteins such as the DNA-J-like homolog and hsp60 play critical roles in preventing protein aggregates (Satyal S H et al., Proc Natl Acad Sci USA 97 5750-5 (2000)), which are known to be critical in Alzheimer's disease (Price D L & Sisodia S S, Annu Rev Neurosci 21: 479-505 (1998), Kovacs D M & Tanzi R E, Cell Mol Life Sci 54: 902-9 (1998); Sisodia S S et al., Am J Hum Genet 65: 7-12 (1999), Tanzi R E & Parson A B (2000), Selkoe D J, Neuron 32: 177-80 (2001)), and could therefore have implications for age-dependent vulnerability to Alzheimer's disease. TABLE 1B ACGs and Genes Showing Highly Significant Age-Dependent Increases in Expression GenBank Description Young Mid Aged ANOVA P behall Inflammation, Defense, Immunity J04488 Ptgds, Prostaglandin D synthase 3976 ± 248 6891 ± 350 8365 ± 438 0.0000 Both X71127 c1qb, complement component 1-q (beta 885 ± 52 1461 ± 85  1895 ± 102 0.0000 Both polypeptide) J03752 Microsomal GST-1, glutathione S-transferase 368 ± 43 695 ± 60 910 ± 45 0.0000 Both L40362* MHC class I RT1.C-type protein 1755 ± 64  2106 ± 82  2501 ± 77  0.0000 Both U17919 Aif1, allograft inflammatory factor 1 712 ± 29 990 ± 47 1152 ± 67  0.0000 Both M15562 MHC class II RT1.u-D-alpha chain 608 ± 73 1194 ± 238 2120 ± 173 0.0000 Both X13044 Cd74, CD74 antigen −49 ± 44 155 ± 83  603 ± 100 0.0000 Both M24324 RTS, MHC class I RT1 (RTS) (u haplotype) 3274 ± 175 4599 ± 363 5822 ± 342 0.0000 Both M32062 Fcgr3, Fc IgG receptor III (low affinity) 347 ± 25 462 ± 32 557 ± 21 0.0000 Both AJ222813 Il18, interleukin 18 110 ± 33 208 ± 14 261 ± 16 0.0002 Both L40364 RT1Aw2, RT1 class Ib 2033 ± 126 2546 ± 127 2842 ± 115 0.0004 Both AI231213 Kangai 1, suppression of tumorigenicity 6 2727 ± 116 2952 ± 120 3484 ± 139 0.0008 Both AI170268 Ptgfr, Prostaglandin F receptor 6651 ± 248 8057 ± 336 8502 ± 359 0.0013 Both X52477 C3, Complement component 3  34 ± 49 236 ± 83  476 ± 100 0.0034 Both X73371 FCGR2, Low affinity immunoglobulin gamma Fc receptor II 218 ± 19 285 ± 24 384 ± 21 0.0001 OMT X78848 Gsta1, Glutathione-S-transferase (alpha type) 3145 ± 74  3909 ± 188 4155 ± 204 0.0009 OMT AA818025* Cd59, CD59 antigen 6465 ± 265 7269 ± 163 7474 ± 189 0.0052 OMT AA891810 GST, Glutathione S-transferase 1136 ± 83  1411 ± 70  1791 ± 101 0.0001 SWM U92081 Gp38, Glycoprotein 38 547 ± 26 679 ± 38 802 ± 66 0.0037 SWM X62322 Grn, Granulin 4514 ± 145 4972 ± 254 5375 ± 119 0.0116 SWM Transcription Regulator X13167* NF1-A, nuclear factor 1 A 112 ± 30 265 ± 38 300 ± 26 0.0008 Both U67082 KZF-1, Kruppel associated box (KRAB) zinc finger 1 472 ± 31 565 ± 32 617 ± 29 0.0099 Both U92564 Roaz, Olf-1/EBF associated Zn finger protein 429 ± 50 687 ± 71 761 ± 50 0.0014 OMT L16995 ADD1, adipocyte determ./different.-dependent factor 1  784 ± 100 1054 ± 75  1179 ± 95  0.0160 OMT AI237535 LitaF, LPS-induced TNF-alpha factor 979 ± 62 1078 ± 68  1338 ± 114 0.0193 OMT AI177161 Nfe212, NF-E2-related factor 2 544 ± 31 590 ± 36 687 ± 25 0.0096 SWM Signal Transduction U26356 S100A1, S100 protein (alpha chain) 1382 ± 105 1636 ± 76  1999 ± 115 0.0008 Both AA850219 Anx3, Annexin A3 438 ± 26 501 ± 21 575 ± 26 0.0023 Both D84477 Rhoa, ras-related homolog A2  749 ± 108 1069 ± 111 1319 ± 85  0.0024 Both AF048828 VDAC1, voltage-dependent anion channel 1 2334 ± 294 3157 ± 392 3844 ± 290 0.0137 Both AI102103 Pik4cb, Phosphatidylinositol 4-kinase 975 ± 63 1029 ± 67  1252 ± 80  0.0247 Both L35921 Ggamma, GTP-binding protein (gamma subunit) 498 ± 30 543 ± 43 712 ± 64 0.0108 SWM M83561 GluR-5, kainate sensitive glutamate receptor 248 ± 23 359 ± 22 351 ± 12 0.0007 None Adhesion, Extracellular Matrix E13541 Cspg5, chondroitin sulfate proteoglycan 5 3938 ± 342 5112 ± 312 5980 ± 242 0.0003 Both X83231 PAIHC3, Pre-alpha-inhibitor, heavy chain 3 2586 ± 110 2974 ± 180 3460 ± 183 0.0038 OMT AF097593 Ca4, cadherin 2-type 1 (neuronal) 615 ± 45 855 ± 61 881 ± 59 0.0049 OMT Myelin-Related Proteins M55534 Cryab, alpha crystallin polypeptide 2 2889 ± 155 4153 ± 196 4621 ± 238 0.0000 Both D28111 MOBP, myelin-associated oligodendrocytic basic protein 13950 ± 386  15483 ± 633  18407 ± 909  0.0004 Both X06554 S-MAG, myelin-associated glycoprotein C-term 5282 ± 258 5595 ± 140 6564 ± 326 0.0038 Both S55427 Pmp, peripheral myelin protein 2458 ± 59  2856 ± 148 3080 ± 129 0.0051 OMT M22357 MAG, myelin-associated glycoprotein  978 ± 163 1544 ± 190 2455 ± 332 0.0010 SWM Lipid Metabolism/Transport X54096 Lcat, Lecithin-cholesterol acyltransferase 187 ± 35 298 ± 30 417 ± 38 0.0003 Both S83279 HSDIV, 17-beta-hydroxysteroid dehydrogenase 630 ± 54 685 ± 91 928 ± 67 0.0182 Both type IV U37138 Sts, Steroid sulfatase 368 ± 74 521 ± 33 587 ± 35 0.0128 OMT X55572 Apod, Apolipoprotein D 5875 ± 355 7281 ± 601 8343 ± 595 0.0133 OMT L07736 Cpt1a, Carnitine palmitoyltransferase 1 alpha (liver) 599 ± 65 677 ± 59 854 ± 59 0.0192 OMT Amino Acid/Transmitter Metabolism J03481 DHPR, Dihydropteridine reductase 13260 ± 369  16897 ± 528  17432 ± 380  0.0000 Both Z50144 Kat2, kynurenine aminotransferase II 106 ± 33 183 ± 19 240 ± 24 0.0040 Both U07971 Transamidinase, mitochondrial 2897 ± 130 3311 ± 186 3644 ± 182 0.0183 OMT M77694 Fah, fumarylacetoacetate hydrolase 847 ± 36 990 ± 49 1305 ± 98  0.0002 SWM Cytoskeletal, Vesicle Fusion X62952 Vim, vimentin  571 ± 100  998 ± 162 1346 ± 122 0.0016 Both AA892333 Tubal, alpha-tubulin −52 ± 83 117 ± 90 357 ± 79 0.0080 Both U11760* Vcp, valosin-containing protein 4314 ± 234 5004 ± 333 5651 ± 278 0.0120 Both U32498* RSEC8, rat homolog of yeast sec8 −11 ± 37 270 ± 81 232 ± 82 0.0236 OMT AF083269* P41-Arc, actin-related protein complex 1b 406 ± 23 488 ± 49 626 ± 72 0.0249 OMT AF028784 GFAP, glial fibrillary acidic protein 19860 ± 714  19731 ± 1002 23241 ± 1058 0.0217 SWM Transporters, Carriers M94918 Hbb, beta hemoglobin 6172 ± 737 8698 ± 646 13715 ± 1017 0.0000 Both U31866 Nclone10 3625 ± 302 5416 ± 561 7407 ± 511 0.0000 Both D38380 Tf, Transferrin 11990 ± 728  16431 ± 707  19831 ± 1519 0.0001 Both X56325 Hba1, alpha 1 hemoglobin 14433 ± 611  17259 ± 959  23893 ± 1426 0.0000 OMT AF008439 Natural resistance-associated macrophage protein 2  69 ± 17 153 ± 19 152 ± 13 0.0018 SWM Growth, Biosynthesis, Maintenance AA799645 FXYD domain-containing ion transport regulator 1 1680 ± 58  2025 ± 68  2457 ± 129 0.0000 Both L03201 Ctss, cathepsin S 17087 ± 393  19066 ± 691  22376 ± 875  0.0001 Both M27905 Rpl21, Ribosomal protein L21 11279 ± 905  13999 ± 389  15557 ± 379  0.0001 Both AA893493 RPL26, Ribosomal protein L26 18442 ± 688  23043 ± 506  24252 ± 1162 0.0001 Both X52619 Rpl28, Ribosomal protein L28 13167 ± 323  13231 ± 310  14520 ± 228  0.0034 Both X14181* RPL18A, Ribosomal protein L18a 8623 ± 430 10171 ± 389  11025 ± 602  0.0068 Both M31076 TNF-alpha, Transforming growth factor (alpha) 139 ± 23 241 ± 43 295 ± 35 0.0167 Both AI171462* Cd24, CD24 antigen 864 ± 69 1270 ± 86  1304 ± 101 0.0026 OMT X68283 Rpl29, Ribosomal protein L29 9705 ± 262 9500 ± 300 10807 ± 267  0.0050 OMT X53504* RPL12, Ribosomal protein L12 9877 ± 328 11398 ± 367  11719 ± 620  0.0241 OMT U77829 Gas-5, growth arrest homolog 173 ± 15 228 ± 14 264 ± 20 0.0030 SWM AI234146 Csrp1, Cysteine rich protein 1 4436 ± 335 4925 ± 207 5451 ± 179 0.0243 SWM Protein Processing and Trafficking M32016 Lamp2, lysosomal-associated membrane protein 2 759 ± 38 906 ± 36 1092 ± 74  0.0008 Both E01534 Rps15, Ribosomal protein S15 16577 ± 368  17202 ± 429  18363 ± 368  0.0116 OMT AI028975 AP-1, adaptor protein complex (beta 1) 1077 ± 38  1163 ± 69  1317 ± 49  0.0158 OMT AI175486 Rps7, Ribosomal protein S7 5820 ± 448 6409 ± 312 7212 ± 208 0.0215 OMT AF023621 Sort1, sortilin 414 ± 34  813 ± 143  812 ± 109 0.0247 OMT AI230712 Pace4, Subtilisin - like endoprotease 281 ± 31 447 ± 49 570 ± 56 0.0010 SWM AA891445* Skd3, suppressor of K⁺ transport defect 3 321 ± 24 440 ± 42 508 ± 37 0.0043 SWM AF031430 Stx7, Syntaxin 7  794 ± 133 1387 ± 188 1461 ± 122 0.0097 SWM AA900516 Pdi2, peptidyl arginine deiminase (type II)  57 ± 42 314 ± 62 344 ± 51 0.0015 None

The analyses for TABLE 1B are as described for TABLE 1A.

Upregulated Genes. Genes that were upregulated with aging and negatively correlated with behavior fit primarily into categories that appeared to reflect activated glial functions (FIGS. 3B and 5, TABLE 1B). Additionally, among the main unexpected findings was a widespread upregulation in the expression of genes encoding proteins for myelin synthesis and lipid turnover (TABLE 1B).

Lipid Metabolism. Multiple genes important for mitochondrial and cytosolic lipid β-oxidation (e.g., carnitine palmitoyltransferase, lecithin-cholesterol acyltransferase, etc.; TABLE 1B), the primary pathway for free fatty acid (FFA) catabolism, were upregulated.

Increased Myelin Synthesis, Cholesterol Biogenesis and Vesicle Transport. Importantly for identifying the trigger mechanism for elevated lipid catabolism, the expression of many genes encoding myelin-related proteins or myelin-related transcription factors on the microarray was increased with aging (and several also were correlated with cognitive impairment) (TABLE 1B). These observations strongly suggest that a major increase in myelin synthesis programs developed with aging. This interpretation is also supported by the upregulation of multiple genes important in lipogenesis for cholesterol biosynthesis (Add 1/SREBP1), and the packaging/transport of cholesterol esters and other complex lipids (ApoD, LCAT, etc.) (TABLE 1B). Recent studies have shown that stimulation of myelin synthesis programs in oligodendrocytes is associated with induction of genes for both myelin proteins and lipogenic pathways (Nagarajan R et al., Neuron 30 355-68 (2001)).

Cyloskeleton/Vesicles. Moreover, expression of genes related to actin assembly, transport or fusion of packaged vesicles (actin related complex, rsec8, tubulin, and syntaxin 7) was increased (TABLE 1B). These molecules are associated with vesicle transport and fusion in neurons. In addition, however actin assembly proteins are also known to play a major role in myelin vesicle transport in oligodendrocytes (Madison D L et al., J Neurochem 72: 988-98 (1999)). Given the upregulation of myelin programs and the downregulation of synaptic plasticity genes, therefore, the age-dependent upregulation of genes linked to vesicle transport capacity seems more likely to be associated with enhanced myelin transport in oligodendrocytes. Further support for the view that extensive oligodendrocyte activation and/or synthesis occurs in hippocampal aging is provided by the observation that many genes that were upregulated with aging are preferentially expressed in oligodendrocytes (e.g., myelin proteins, FAH, PGD-S, etc.) (e.g., Labelle Y et al., Biochim Biophys Acta 1180: 250-6 (1993)).

Myelin also is normally degraded to free fatty acids through the endosomal-lysosomal pathway. Consistent with elevation of myelin degradation, we also found increased expression of Cathepsin S and other genes encoding lysosomal enzymes (TABLE 1B). Cathepsin S is particularly important in the processing of antigenic myelin fragments.

Amino Acids. In contrast to enzymes for glucogenic amino acids (TABLE 1A), expression was upregulated for multiple genes encoding enzymes related to the metabolism of the ketogenic/glucogenic amino acids, tyrosine, phenylalanine and tryptophan (e.g., DHPR, KAT, FAH, see, TABLE 1B). Catabolism of ketogenic amino acids yields either acetoacetate or one of its precursors (e.g., acetyl CoA), which can be used either for energy metabolism or lipogenesis. Upregulation of DHPR, which catalyzes the formation of a critical cofactor (tetrahydrobiopterin) for tyrosine and monoamine synthesis, and concomitant upregulation of MAO-B (TABLE 3), together suggest elevated metabolism of tyrosine and tryptophan via greater monoamine turnover.

Inflammation/Defense/Immunity. There was massive upregulation of expression of genes encoding MHC class I antigen presenting molecules, and numerous other inflammatory/immune proteins (TABLE 1B). Genes in the inflammation category exhibited some of the most robust monotonic changes with aging seen in our results using the method of the invention (e.g., most were significant at the p<0.001 criterion with 0.025 FDR) (TABLE 1B). Moreover, most were inversely correlated with cognitive function (FIG. 3B).

Consistent with evidence of a role for oxidative stress in brain aging (Carney J M et al., Proc Natl Acad Sci USA 88: 3633-6 (1991), Hensley K et al., Ann NY Acad Sci 786: 120-34 (1996), Bickford P C et al., Brain Res 866: 211-7 (2000), Lee C K et al. Nat Genet 25: 294-7 (2000), Jiang C H et al., Proc Natl Acad Sci USA 98: 1930-4 (2001)), we also found increased expression for molecules important in defense against oxidative stress (GST, GSTa1) (TABLE 1B). One potentially key new finding here, as noted above, was that DHPR was upregulated with aging and correlated with cognitive decline (TABLE 1B). Its product, tetrahydrobiopterin, is also an essential cofactor for nitric oxide synthase (Boyhan A, et al. Biochem J 323 (Pt 1) 131-9 (1997)). Because oxyradicals formed from nitric oxide appear to play a major role in inflammatory neuronal damage (Bal-Price A & Brown G C, J Neurosci 21: 6480-91 (2001), Calingasan N Y & Gibson G E, Brain Res 885: 62-9 (2000)), this may be an important pathway through which the deleterious effects of inflammation are mediated in brain aging.

Glial Markers. Astrocyte reactivity and astrocyte markers are also well recognized to increase in the aged rodent and human hippocampus (Landfield P W et al., Science 214: 581-4 (1981), Landfield P W et al., J Neurobiol 23: 1247-60 (1992), Nichols N R et al., Neurobiol Aging 14: 421-9 (1993), Finch C E & Longo V D, Neuroinflammatory Mechanisms in Alzheimer's Disease: Basic and Clinical Research, 237-256 (2001)) and the present data confirm extensive upregulation of genes (Finch C E & Tanzi R E Science 278: 407-11 (1997)) for glial markers (e.g., vimentin, GFAP-cytoskeleton category, TABLE 1B). In addition, we extended those observations to show that genes for proteoglycans (TABLE 1B) and other extracellular proteins (e.g., fibronectin) that are components of astroglial scars also were upregulated. These changes may reflect astroglial-mediated reorganization of the extracellular matrix, a process known to be unfavorable for axonal remodeling.

Signal Transduction. Several genes in calcium regulating and G-protein-coupled signaling pathways were also identified (TABLE 1B). In particular, S100A1, which modulated Ca²⁺-induced Ca²⁺ release, and PI 4-kinase, which acts to produce IP3 were upregulated. Several other S100-related genes (e.g., S100A4 and P9K2; TABLE 3) were also upregulated with aging but failed to meet the strict criteria set forth herein (FIG. 2).

Biosynthesis. Concomitantly, many ribosomal (growth) and protein processing genes were upregulated (TABLE 1B). The upregulated changes reflect increased protein synthesis, turnover and phagocytosis associated with strongly elevated biosynthetic processes in glial compartments (e.g., elevated myelin, MHC, proteoglycan synthesis).

Orchestrating Factors. Our data show that a number of transcriptional regulators and cytokines, including KZF-1, Roaz and members of the NFI family (TABLE 1B) were upregulated and therefore, may be strong candidates for coordinating factors. Under some conditions, several of these factors function as negative transcriptional regulators.

Relationship to Fold Change. The large majority of microarray analyses to date have used fold-change criteria to detect changes in expression. In addition to providing little basis for statistical assessment (e.g., Miller R A, et al. J Gerontol A Biol Sci Med Sci 56 B52-7 (2001)), however, fold-change criteria are relative insensitive. Among the 139 ACGs, most exhibited group mean fold changes between the Young and Aged groups of less than 1.5 (92), a few showed fold changes between 1.5 and 2.0 (26), and only a handful of genes exceeded 2-fold-change (20) (TABLES 1A and B). Thus, few of our results using the method of the invention would have been detected in the great majority of prior microarray studies, in which 1.7 to 2-fold change cutoffs are commonly used as minimum criteria for identifying differences, and many changes are reported in the 3-4 fold range. Further, the rank order correlation between group mean fold-change and p values on the ANOVA for all aging-significant genes, although significant, was modest according to Spearman's correlation test (Spearman's r=0.45, p<0.001). Armitage P & Berry G, Statistical Methods in Medical Research, 2^(nd) Edn., 200-205 (1987). This indicates that fold-change accounted for only 20% of the variance (r2) in the degree of statistical significance on the ANOVA. Some of our results detected with the enhanced sensitivity of statistical analysis were extremely subtle (e.g., 1.1 fold for the L28 and L29 ribosomal proteins, TABLE 1B). Despite this enhanced sensitivity, however, numerous false negatives were still undoubtedly present in our data set.

Age Course of Gene Expression Changes. Using a design with three age groups enabled us to classify genes and categories according to their general patterns of age dependence of change (FIGS. 4 and 5). Genes were classified by whether 75% of the maximal change occurred between the Young and Mid-Aged groups (Yng to Mid), the Mid-Aged and Aged groups (Mid to Aged), or the Young and Aged groups (monotonic).

Almost all categories comprising downregulated and cognitively correlated genes (TABLE 1A), exhibited their greatest change between the Young and Mid-Aged points, and many did not show much additional downregulation between the Mid-Aged and Aged groups (FIG. 4). This was also true for the entire population of genes whose expression decreased with aging at p<0.025 (pie-chart inset, FIG. 4). Conversely, by far the largest fraction of functional categories of upregulated genes showed a monotonic age course of change that also began between the Young and Mid-Aged points but, in addition, continued between the Mid-Aged and Aged points (FIG. 5). However, the Cytoskeletal and Transcriptional Regulator categories contained significant numbers of exceptions that exhibited >75% of their change between the Young and Mid-Aged groups (TABLE 1B). Additionally, among all genes that showed significant upregulation with aging, the majority fit the monotonic classification (pie-chart inset, FIG. 5). Only a few scattered genes showed a predominantly Mid to Aged change pattern (e.g., FIGS. 4 and 5 pie-charts).

Strongest Correlations of Pathways with Memory Performance. To determine which pathways were most closely correlated with memory performance, we calculated the percentage of genes in each of our categories that were correlated significantly (at p<0.025) with both memory tests. We reasoned that each test measures aspects of memory but each test also has its own error sources and confounding contributions from non-cognitive performance factors. Therefore, genes that correlated with both tasks seem more likely to be associated with cognitive processes.

Because memory performance changed most between the Mid-Aged and Aged groups (FIG. 1), whereas downregulated genes changed little (FIG. 4) and upregulated genes continued to increase (FIG. 5) between those groups, the pattern of age course changes relative to cognitive performance was more similar for upregulated than for down-regulated genes. Not surprisingly, therefore, more upregulated (52%) than downregulated (44%) genes were correlated with performance on both tasks. Three categories of downregulated genes had 50% or higher both-task correlations: Adhesion and extracellular matrix (⅗), Metabolism ({fraction (8/10)}), and Protein processing and trafficking (⅗). Whereas seven categories of upregulated genes had 50% or higher both-task correlations: Signaling ({fraction (5/7)}), Inflammation ({fraction (14/20)}), Cytoskeleton/Vesicle ({fraction (3/6)}), Myelin related proteins (⅗), Amino acid/transmitter metabolism ({fraction (2/4)}), Transporters and carriers (⅗), and Growth, biosynthesis, maintenance ({fraction (7/12)}). In the Signaling category, moreover, genes involved in intracellular Ca²⁺ release, S100A1 and PI3-K (TABLE 1B), were correlated with both tasks.

Another way to examine closeness of correlation specifically with memory impairment is to correlate gene expression with performance only in the aged group. This correlation focuses on variation in the performance of aged animals and removes the overall age course pattern from contributing to the correlation with impairment. This correlation is independent of the ANOVA for aging effects and an FDR also can be calculated. Consequently, we tested each of the 139 primary aging- and behaviorally-related genes for correlation with 24 hr memory performance on the OMT in the aged group. The OMT was selected over the SWM for this test as it had the greater dispersion of performance needed for correlation analysis. The correlation tests in the aged group (n=10) of course had considerably less power than across all three groups (n=29) and the criterion for significance was set at p<0.025.

Only 3 (4.9%) of the downregulated ACGs, but 10 (12.2%) of the upregulated ACGs were correlated with Aged group performance on the OMT. The FDR for these genes was 0.28. Two of the 3 downregulated ACGs were accounted for by the Synaptic Structural Plasticity category (Fez-1, agrin). For upregulated genes, two of the 10 ACGs were from Inflammation (MHC and CD59 antigen), three from Cytoskeleton/Vesicle category (Vcp, rsec8 and p41-Arc), and three from Growth/Biosynthesis (2 ribosomal proteins and CD24 antigen). No other category had more than one, including Transcription (NF1-A) and Protein processing and trafficking (Skd3).

Thus, by the criterion of correlation on both tasks, the upregulated categories of Inflammation/Immune, signaling (particularly Ca²⁺ signaling), Cytoskeleton/Vesicle and Amino Acid Metabolism were ranked most highly. By the criterion of correlation in the aged group only, the upregulated categories of Cytoskeleton/Vesicle ({fraction (3/6)}), Biosynthesis ({fraction (3/12)}) and Inflammation ({fraction (2/20)}), and the downregulated category of Synaptic Plasticity ({fraction (2/7)}) were ranked most highly.

Benefits of the Invention. One of the major problems associated with developing treatments for aging-dependent functional decline is the lack of good genomic biomarkers or targets of brain aging needed for evaluating the efficacy of different treatments. Our ACGs, therefore, could serve as excellent biomarkers of cognitive aging. Using microarrays constructed to contain oligonucleotide sequences specific for hybridization with and measurement of mRNAs of the identified ACGs, laboratory animals could be assessed for degree of cognitive aging before, during and after treatment with a compound. Treatments that slowed or reversed the ACG profile during aging might be highly promising for development as new therapeutic approaches. Further, treatments that slowed or reversed expression profiles of particular genes in our panel of biomarkers might reveal which specific genes among the subset of ACGs are most critical for the age-dependent functional decline and, therefore, would suggest genes and gene products that should be targeted with high priority for development of therapeutic interventions. The same approach could be applied using our panel of unique brain aging genes that are not specifically clustered with cognition related genes, to evaluate and develop new therapies and compounds for treatment of brain aging in general.

The panel of ACGs identified here can be used on a microarray to perform diagnostic tests. Subjects suspected of having accelerated brain aging or early age-related neurodegenerative disease could provide a small brain biopsy sample for testing by microarray. This could then determine the subject's suitability for pharmacologic intervention.

Based on the gene lists described above, investigators can develop new drugs or treatments aimed at altering the activity of one or more genes in the lists, or products encoded by those genes, or targets of the products, with the goal of counteracting age-related cognitive impairment or brain aging in general.

A smaller subset of ACGs, specifically linked to some process or system (e.g., to inflammation, mitochondrial function, or lipid metabolism, etc.), could be used in a microarray to test efficacy of a new compound targeted to slowing or reversing aging and cognitive changes dependent on that set of genes or gene-impacted systems, either in experimental tests to develop new compounds, or as diagnostic or therapeutic guides.

Relevance to Human Brain Aging and Alzheimer's Disease. Normal human brain aging is associated with memory dysfunction and appears to set the stage for Alzheimer's disease and other age-related neurodegenerative conditions. It also shares many features with animal models of aging. Landfield P W et al., J Neurobiol 23: 1247-1260 (1992). Thus, many of the memory-correlated gene expression profiles seen here in rats may have implications for genomic mechanisms of human brain aging and/or Alzheimer's disease. This view is supported by several parallels between processes identified here and those seen in human aging or Alzheimer's disease. For example, myelin abnormalities are also found extensively in normal brain aging in humans (leukoaraiosis). These white matter changes in humans are also correlated with cognitive dysfunction and become more severe in disease states. Further, cerebral metabolism begins to decline by mid-life in humans, much as it apparently does in rats (FIG. 4). Of particular note in light of our findings on oxidative phosphorylation and myelin turnover, mitochondrial diseases in humans also can result directly in demyelination.

It is interesting, in view of the apparently altered lipid metabolism seen here, that activity of the cholesterol ester synthesizing enzyme acyl CoA:cholesterol acyltransferase (ACAT) is elevated in Alzheimer's disease and appears directly coupled to amyloid production. ACAT has lipogenic functions somewhat similar to those of LCAT, which was also upregulated here (TABLE 1A). Moreover, activity of glycerol-3-phosphate dehydrogenase (GPDH) is elevated in association with abnormal glucose metabolism in brains of patients with Down's syndrome. The gene encoding this glycolytic enzyme was also upregulated here (TABLE 1A). Other processes found in human aging or Alzheimer's disease brain for which we found corollaries in gene expression include, as noted, inflammation, oxidative stress and elevated KatII (kynurenine aminotransferase 2), among others. Thus, if these parallels depend, at least in part, on similar mechanisms, our our results show that widespread genomic regulatory changes would reasonably be expected to contribute to altered cerebral metabolism, lipid synthesis, neural activity and myelination in human brain aging as well.

Implications for a New Hypothesis of Brain Aging. Based on the functional implications of our results, as discussed above, we provide a new working model of brain aging (FIG. 6). Early in adult life (i.e., before mid-life) a series of brain changes begin, perhaps initiated by new expression of genes that exert deleterious late-life actions (e.g., “late genes”) (Finch C E, Longevity, Senescence and the Genome, 37-42 (Univ. Chicago Press, Chicago, 1990); Austad, S N, Why We Age: What Science Is Discovering about the Body's Journey Through Life (Indianapolis, Wiley, 1999)) or by catabolic hormonal processes (e.g., glucocorticoids, Porter N M & Landfield P W, Nature Neurosci 1: 3-4 (1998)). These changes include reduced neuronal activity and induce a subtle shift from anabolic to catabolic metabolism in neurons. In neurons, the reduced anabolic capacity leads to diminished capacity for protein biosynthesis and, in particular, for activity-dependent neurite remodeling and synaptogenesis. Concomitantly, an increase in degradation of myelin and lipids begins, perhaps triggered by reduced neural activity, or reduced oxidative phosphorylation and/or demand for an alternative energy source, or by an immune process similar to multiple sclerosis, among other possibilities. The degenerating myelin fragments are endocytosed in microglia and astrocytes, degraded by lysosomes and packaged into antigen-presenting MHC molecules. This in turn activates orchestrating cytokines and transcription factors that trigger an inflammatory reaction in the glia and possibly, in macrophages. The inflammation further accelerates the phagocytosis and degradation of myelin. As astrocytes hypertrophy, they increase glycolytic metabolism and synthesize “glial scar” proteins (e.g., fibronectins, proteoglycans) that alter the extracellular matrix. In oligodendrocytes, lipogenic and myelin synthesis programs are activated in response to the ongoing demyelination and/or altered signaling pathways. In turn, remyelination may increase demand for lipid substrate and thereby also accelerate demyelination. Thus, positive feedback cycles between demyelination and myelination and/or between demyelination and inflammation, among other processes, might develop and further drive cellular dyshomeostasis. Eventually, the reduced synaptogenic capacity unfavorable extracellular matrix and degradative inflammatory processes result in failure of cognitive processing. Additionally, the ongoing catabolic processes erode neuronal membranes and cytoskeletons, increase protein aggregation and enhance vulnerability to neurodegenerative disease. Accordingly, our results, in conjunction with this working model, point directly to potentially useful therapeutic interventions and should, therefore, facilitate the design of such future therapeutics.

The details of one or more embodiments of the invention are set forth in the accompanying description above. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. Other features, objects, and advantages of the invention will be apparent from the description and from the claims. In the specification and the appended claims, the singular forms include plural referents unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. All patents and publications cited in this specification are incorporated by reference.

The following EXAMPLES are presented in order to more fully illustrate the preferred embodiments of the invention. These examples should in no way be construed as limiting the scope of the invention, as defined by the appended claims.

EXAMPLE 1

Behavioral Results

Thirty animals in three age groups (n=10/group) were trained sequentially on two tasks, first in the Morris spatial water maze (SWM) and then in the object memory task (OMT). Male Fischer 344 rats aged 4 months (Young, n=10), 13 months (Mid-Aged, n=10) and 24 months (Aged, n=10) were used. Overall, the training/testing lasted seven days, and hippocampal tissue was collected 24 hr later. Training or testing occurred on each day except for the 2^(nd) and 3^(rd) days of the seven-day sequence.

Methods used here for cognition assessment in the Morris Spatial Water Maze (SWM), a task sensitive to both hippocampal function and aging, have been described previously Norris C M & Foster T C, Neurobiol Learn Mem 71, 194-206 (1999). Briefly, rats were trained in a black tank, 1.7 M in diameter, filled with water (27±2° C.). Behavioral data were acquired with a Columbus Instruments tracking system. After habituation to the pool, animals were given cue training with a visible platform (five blocks of three trials, maximum of 60 sec/trial, 20 sec intertrial interval and a 15 min interval between blocks). Rats remained in home cages under warm air after each block. Cue training was massed into a single day and the criterion for learning was finding the platform on 4 of the last 6 trials. For all animals that met this criterion, spatial discrimination training was initiated three days later in which the escape platform was hidden beneath the water but remained in the same location relative to the distal cues in the room. Fifteen min following the end of spatial training, a 1-min duration free-swim probe trial with the platform absent was administered, during which crossings over the former platform site (platform crossings) were recorded to test acquisition, followed by a refresher training block. Retention for platform location was again tested 24-hr later using a second 1-min free-swim probe trial.

During cue training in the SWM, all animals were able to locate the visible escape platform according to our criteria and therefore, were trained on the hidden platform spatial task. During acquisition, Aged animals performed more poorly (longer latencies) than Mid-Aged or Young. In addition, an aging-dependent decrease in 24 hr retention, measured by platform crossings (1-way ANOVA, p<0.05), was observed on the retention probe trial (FIG. 1A). Post hoc analysis indicated that Young and Mid-Aged animals exhibited more platform crossings relative to Aged animals, but did not differ from each other.

Methods used here for cognition assessment in the object memory task OMT) have been described previously by Ennaceur A & Delacour J, Behav Brain Res 31: 47-59. (1988). The object memory task (OMT) is also both sensitive to hippocampal function and affected by aging but is less dependent on physical strength and endurance. On the afternoon of the final spatial maze probe trial, animals were administered a habituation session (15-min) in the empty mesh cage to be used for the OMT (63.5 cm×63.5 cm). OMT training began 24 hr after habituation and consisted of a 15-min acquisition session during which two 3-dimensional objects were placed at opposite sides of the cage, followed by two 15-min retention test sessions at 1 and 24 hr posttraining. During the acquisition session, the cage contained two sample objects (A and B) and the time spent actively exploring each object was recorded. After 1 hr, the rat was reintroduced into the cage and the time spent exploring a novel object, C, relative to the familiar object, B, was recorded. On the 24 hr test, familiar object A was reintroduced and object B was replaced by a second novel object, D. Objects were randomized across individuals and timed measures of exploration were used to calculate a memory index (MI) as follows: MI=(N−F)/T, where N is time spent exploring the novel object, F is time spent exploring the familiar object, and Tis total time spent exploring the two objects. More time spent exploring the novel object (higher MI) is considered to reflect greater memory retention for the familiar object.

In the OMT, Aged animals performed as well as Young or Mid-Aged on the 1 hr retention test (not shown), but there was a significant age-related decline in recall (1-way ANOVA, p<0.001, for the main effect of age) on the 24 hr test (FIG. 1B). At 24 hr, Young and Mid-Aged groups were significantly different from the Aged group, but not from one another (Young vs. Aged: p<0.001; Mid-Aged vs. Aged: p<0.05; Young vs. Mid-Aged: N.S., Tukey's post-hoc test; Armitage P & Berry G, Statistical Methods in Medical Research, 2^(nd) Edn., 200-205 (1987)).

EXAMPLE 2

Gene Microarray Chip Results

Microarray analyses were performed on hippocampal CA1 tissues from each of the same behaviorally characterized 30 animals (one chip per animal), but one chip was lost for technical reasons, leaving a data set of 29 microarrays (Young=9, Mid-Aged=10, Aged=10). For tissue preparation, twenty-four hours after completion of the OMT testing, animals were anesthetized with CO₂ gas and decapitated. The brains were rapidly removed and immersed in ice-cold, oxygenated artificial cerebrospinal fluid consisting of (in mM): 124 NaCl, 2 KCl, 1.25 KH₂PO₄, 2 MgSO₄, 0.5 CaCl₂, 26 NaHCO₃, and 10 dextrose. Hippocampi were removed and the CA1 region from one hippocampus per animal were dissected by hand under a stereomicroscope. The CA1 tissue block from each animal was placed in a microcentrifuge tube and flash frozen in dry ice for RNA isolation.

For RNA isolation, total RNA was isolated using the TRIzol reagent and following the manufacturer's RNA isolation protocol (Gibco BRL, #15596). One ml of TRIzol solution was added to each tube containing the frozen tissue block and the tissue was homogenized by 10 passages through an 18½ G syringe needle. After centrifugation, the RNA was precipitated from the aqueous layer, washed and redissolved in RNase-free water. RNA concentration and the integrity of RNA were assessed by spectophotometry and gel electrophoresis. The RNA samples were stored at −80° C.

Gene expression analyses were performed using the Affymetrix GeneChip System. The labeling of RNA samples, rat GeneChip (RG-U34A) hybridization and array scanning were carried out according to the Affymetrix GeneChip Expression Analysis Manual (r.4.0, 2000). Each animal's CA1 RNA was processed and run on a separate rat gene chip. Briefly, an average yield of 40 μg biotin-labeled cRNA target was obtained from 5 μg of total RNA from each CA1 sample, of which 20 ug cRNA was applied to one chip. The hybridization was run overnight in a rotating oven (Affymetrix) at 45° C. The chips were then washed and stained on a fluidics station (Affymetrix) and scanned at a resolution of 3 μm in a confocal scanner (Agilent Affymetrix GeneArray Scanner).

Each U34A rat chip (Affymetrix, Santa Clara, Calif.) contained 8,799 transcript probe sets (gene representations). Although the measured signal intensity for a transcript probe set (Methods) reflects mRNA content, it is referred to here as “gene expression”. However, it is well recognized that mRNA stability and other factors in addition to gene transcription can affect mRNA content.

We used the microarray suite (MAS 4.0) software (Affymetrix) to calculate the overall noise of the image (the amount of variation around the mean intensity, Qraw) for each array. Overall noise was highly similar across arrays in all 3 age groups (Young: 21.81±1.55; Mid Aged: 21.25±2.24; Aged: 20.66±2.06, N.S.). “All probe set scaling” was used to set overall intensities of different arrays to an arbitrary target central intensity of 1500. Thus, the average intensity of each array was adjusted to the 1500 value using a scaling factor (SF). There was no significant difference in SF across ages (Young: 1.58±0.14; Mid Aged: 1.46±0.20; Aged: 1.63±0.16, N.S.).

The algorithm used to determine Presence/Absence is listed in the Microarray Suite 4.0 Manual and is the basis upon which a particular transcript is determined to be reliably detectable by a given probe set. Average difference scores, the average of the difference in expression intensity (ADEI) of each probe pair within a probe set, formed the basis for determining expression (relative abundance) of transcripts, and throughout the text the term “expression level” refers to the ADEI score. When comparing across appropriately normalized arrays, the larger the ADEI score, the greater the relative expression for that particular message. However, ADEI scores are not comparable for relative expression levels among different messages on the same chip, as there are several other factors that can confound such an assessment (e.g., p. 356, Affymetrix Microarray Suite 4.0 User's Guide).

The Presence/Absence calls and Average Difference scores for all probe sets on all 29 arrays were then copied from the MAS pivot table to an Excel 9.0 (Microsoft, SR-1) workbook. From within Excel, the following data manipulations were performed.

Min-Max: For the purposes of filtering (FIG. 2), each probe set was normalized according to the formula: ${x^{\prime} = \frac{x - {\overset{\_}{X}\quad\min}}{{X\quad\max} - {X\quad\min}}},$ where x is ADEI score, {overscore (X)}_(min) is the mean for the age group with the lowest ADEI score, and {overscore (X)}_(max) is the mean for the age group with the largest ADEI score. Thus, normalized mean values varied between 0 (lowest) and 1 (highest) for each probe set.

Standardization (Z-score): For the purpose of obtaining the mathematical means within functional categories and graphing, the data was normalized using the Z-score method: ${z = \frac{x - \overset{\_}{X}}{{SD}(x)}},$ where {overscore (X)} is the mean, and SD(x) is the standard deviation of ADEI across all age groups for an individual probe set.

Statistical Analysis. All statistical tests were performed using a combination Excel (Microsoft, version 9, SR-1) and Sigma Stat (SPSS, version 2).

EXAMPLE 3

Multi-Step Gene Identification Algorithm

The analytic algorithm of the invention, which addresses the bioinformatics issues noted above, comprise three main steps aimed first, at reducing the number of comparisons (to manage type I error), second, at reliably detecting modest aging differences with global statistical analyses (by ANOVA), and third, at identifying aging-related expression changes that were quantitatively correlated with cognitive function (by Pearson's test; Armitage P & Berry G Statistical Methods in Medical Research, 2^(nd) Edn., 200-205 (1987)) (see, FIG. 2).

Multiple Comparison Reduction Step. The expected false positives in a series of multiple comparisons (false positive rate) are predicted to be a percentage of the total statistical comparisons to be made, as defined by the p-value (i.e., tests at p<0.05 will on average generate 5% false positives). Accordingly, the absolute numbers of expected false positives can be decreased simply by reducing the total transcript sets that are tested in a microarray analysis. This can be done by deleting all transcripts identified a priori as not likely to be relevant to the specific interests of the analysis.

Using this step of the method, we reduced the total transcripts to be tested in three phases. In the first phase, we deleted quality control oligonucleotide sets (“control”, n=60) and all gene transcripts (probe sets) rated “absent” by our criteria. As used in this specification, the term “quality control oligonucleotides” are those oligonucleotides and polypeptides used to test for the appropriate behavior of the technological system, rather than to measure expression levels of biological interest.

Of the original 8,799 sets, 4,118 gene transcript sets were removed at this stage, leaving 4,681 transcript sets that were called “present” for further consideration (FIG. 2, step 1a). In the second phase, we deleted all “present” transcript sets representing “expressed sequence tags” (ESTs), which have not yet been clearly linked to known genes (FIG. 2, step 1b). There were 1,213 such ESTs rated “present” that we filtered out in this phase, leaving 3,468 transcript sets for further consideration. The third reduction phase was based on our interest in persistent aging-dependent changes reflected in substantial differences between the youngest and oldest groups. We further decreased the total transcript sets to be tested by deleting sets in which the difference between the Young and the Aged group did not comprise at least 75% of the maximum normalized difference among groups (i.e., in which age-related changes from the Young baseline values were maximal in the Mid-Aged group, but then reversed substantially (>25%) in the Aged group, possibly because of random, compensatory or developmental factors). There were 1,483 sets removed by this criterion, retaining 1,985 probe sets of the original 8,799 for formal statistical testing (FIG. 2; step 2). If the original 8,799 sets had been tested at the p<0.025 alpha level, ˜420 false positives would have been expected. However, by reducing the total number of sets to be tested for statistical significance (at p<0.025), we reduced the absolute numbers of false positives expected from multiple tests, to ˜50 (5% of 1985).

Group Statistical Testing Step (ANOVA). In this second main step of the algorithm, each of the remaining 1,985 transcript sets was tested by 1-way ANOVA for a significant effect of aging (at p≦0.025) across the 3 age groups (n=9-10/group). Of the 1,985 tested sets, 233 were found to change significantly with aging (observed total positives). As noted, at p<0.025, approximately 2.5% (50) of the 1,985 tested should be significant by chance alone (expected false positives). In order to estimate the proportion of false discoveries anticipated among our 233 observed positives (i.e., the fraction of observed positives expected to be false), we used the expected false positive value to calculate the false discovery rate (FDR) (Benjamini et al., Behav Brain Res 125: 279-284 (2001)). For any multiple comparison, the false discovery rate provides an empirical estimate of the anticipated chance error rate among all positives detected. It is partly analogous to the p value of statistical tests, in that the false discovery rate yields the probability that any positive found at the alpha level used (in this case p<0.025) is positive by chance alone.

For the ANOVA-positive results, the FDR was 50/233=0.21, indicating that up to 21% of the observed positives might be positive by chance alone or, that any one positive had a 21% chance of being a false positive.

In addition, we examined the FDR obtained using two other ANOVA p-value levels, p<0.01 and p<0.001. At the p<0.01, ˜20 genes should be found positive by chance alone among the 1,983 transcripts tested. A total of 145 total positives were observed, yielding an FDR of 20/145=0.14. At p<0.001 only 2 false positives are expected in 1,983 tests, and 70 total positives were found. This yields a FDR of 2/70=0.03. The latter, in particular, compares highly favorably with the 0.05 alpha level conventionally accepted for statistical significance in univariate analyses.

However, as noted, additional confidence and validation is gained in microarray analyses when similar patterns of regulation are found among multiple functionally similar genes (Prolla et al., J Gerontol A Biol Sci Med Sci 56: B327-330 (2001)). This is because such genes are not necessarily independent and their co-regulation can provide added cross-validation (e.g., Mimics et al., Neuron 28: 53-67 (2000); Prolla et al., J Gerontol A Biol Sci Med Sci 56: B327-330 (2001)). Consequently, in many cases, confidence advantages can be gained by relaxing p-value criteria in order to expand the numbers of genes included in functional categories. Mimics K, Nat Rev Neurosci 2: 444-447 (2001). Further, relaxing stringency of the p-value reduces the likelihood of type II error (false negatives). Based on these rationales, we used the set of 233 genes obtained at the less stringent p≦0.025 alpha level (rather than the set of 70 at p≦0.001) for the next main step of our algorithm, the behavioral correlation analysis (FIG. 2, step 3a).

Cognitive Performance Correlation Step (Pearson's Test). In this step we identify a specific subset of the 233 aging-significant (by ANOVA) genes that was also correlated with memory performance in both the OMT and SWM. We tested each of the 233 ANOVA-significant genes across animals for statistical correlation between that gene's expression value and behavioral scores (with Pearson's test).

The expression of 161 of the 233 ANOVA-significant genes was correlated significantly with behavioral performance on memory-dependent tasks (p≦0.025; ACGs). Of these, 84 were significantly correlated with both OMT and SWM performance, 40 were significantly correlated with OMT, and 37 were significantly correlated with SMW (FIG. 2, step 3a). Of the 233 genes significant by ANOVA across age, 72 were significantly correlated with neither OMT nor SWM. Of these, 11 were significant by ANOVA across age at the more stringent p-value of ≦0.001 (FIG. 2, step 3b) and were included for further analysis. Of the 161 ACGs, 64 exhibited decreased expression with aging and 97 exhibited increased expression with aging. Examples of the correlation patterns with behavior in the Aged group for the genes with the five highest correlations in each direction are shown in FIG. 3.

Because of the voluminous literature involved, many relevant citations are not included here. In addition to the “dual function” status of some genes, the functions of many are not completely understood, and therefore, the categorization here, while generally consistent with published reports, is not definitive.

ACGs that were downregulated with aging (TABLE 1A) appeared primarily to represent metabolic and neuronal functions. A substantial number of them fell into the category of oxidative metabolism (TABLE 1A). Many also fell into categories of synaptic/neuritic remodeling or other activity-dependent neuronal processes, e.g., immediate early genes (IEGs) (TABLE 1A). Conversely, ACGs that were upregulated with aging fit primarily into categories that appeared to reflect activated inflammatory response (TABLE 1B).

Additionally, among the main unexpected findings was a widespread upregulation in the expression of multiple genes encoding proteins for myelin synthesis (TABLE 1B) and lipid turnover (TABLE 1B). These various categories, overall, are consistent with a downward shift of oxidative metabolism in parallel with a major upregulation of lipid metabolism.

EXAMPLE 4

Genes Identified by the Method of the Invention

The following tables provide additional results from the tests performed above, and supplement the results presented in TABLES 1A and B. TABLE 2 ESTs That Were Aging And Cognition Related or Showed Highly Significant Age-Dependent Changes in Expression Level GenBank Description Young Mid Age FC ANOVA p Decreased with Age Correlated with both OMT and SWM AA963449 UI-R-E1-gj-e-08-0-UI.s1 cDNA 2499 ± 80  2122 ± 102 1874 ± 37  −1.33 0.0000 AA892532 EST196335 cDNA 4156 ± 85  4194 ± 80  3715 ± 100 −1.12 0.0010 AA859626 UI-R-E0-bs-h-02-0-UI.s1 cDNA 853 ± 22 705 ± 23 714 ± 35 −1.20 0.0013 AA893743 EST197546 cDNA 2292 ± 63  1985 ± 80  1846 ± 92  −1.24 0.0022 AI233365 EST230053 cDNA 8460 ± 232 7572 ± 289 7151 ± 226 −1.18 0.0042 H31665 EST105952 cDNA 1160 ± 56  1017 ± 34  942 ± 38 −1.23 0.0051 AA892353 ESTs, Moderately similar to JC5823 NADH 890 ± 59 796 ± 66 602 ± 47 −1.48 0.0054 dehydrogenase AI639247 mixed-tissue library cDNA clone rx03939 3 945 ± 36 814 ± 45 749 ± 36 −1.26 0.0063 AA858617 UI-R-E0-bq-b-06-0-UI.s1 cDNA 397 ± 17 294 ± 32 285 ± 22 −1.39 0.0072 AI639429 mixed-tissue library cDNA clone rx00973 3 341 ± 31 350 ± 22 252 ± 21 −1.35 0.0148 AA858620 UI-R-E0-bq-b-09-0-UI.s1 cDNA 153 ± 24  93 ± 10  86 ± 14 −1.78 0.0160 Correlated with OMT AA866291 UI-R-A0-ac-e-12-0-UI.s3 cDNA 13818 ± 281  12477 ± 171  11987 ± 406  −1.15 0.0008 AA894104 EST197907 cDNA 5716 ± 164 5259 ± 156 4871 ± 179 −1.17 0.0060 AA799996 EST189493 cDNA 4881 ± 67  4812 ± 110 4407 ± 120 −1.11 0.0066 AA892805 EST196608 cDNA 6563 ± 147 6174 ± 247 5645 ± 212 −1.16 0.0176 AI639019 mixed-tissue library cDNA clone rx01107 3 353 ± 19 315 ± 24 265 ± 16 −1.33 0.0188 AA799538 EST189035 cDNA 1436 ± 156 1337 ± 76   963 ± 117 −1.49 0.0211 Correlated with SWM AI070108 UI-R-Y0-lu-a-09-0-UI.s1 cDNA 1542 ± 36  1327 ± 39  1307 ± 58  −1.18 0.0022 AA866409 UI-R-E0-ch-a-03-0-UI.s1 cDNA 994 ± 38 814 ± 37 819 ± 35 −1.21 0.0026 AA859632 UI-R-E0-bs-h-08-0-UI.s1 cDNA 415 ± 53 352 ± 17 247 ± 18 −1.68 0.0040 AA891651 EST195454 cDNA 16635 ± 723  15405 ± 589  13530 ± 521  −1.23 0.0051 AA893032 ESTs, Moderately similar to CALX calnexin 606 ± 26 491 ± 30 501 ± 17 −1.21 0.0060 precursor AA891965 EST195768 cDNA 2353 ± 55  2260 ± 60  2088 ± 45  −1.13 0.0060 AA800708 ESTs, Weakly similar to S28312 hypothetical 1042 ± 38  945 ± 43 805 ± 58 −1.29 0.0065 protein F02A9.4 AA964320 UI-R-C0-gu-e-09-0-UI.s1 cDNA 18110 ± 355  17683 ± 319  16605 ± 293  −1.09 0.0082 AA893173 EST196976 cDNA 9712 ± 294 8674 ± 503 8155 ± 222 −1.19 0.0196 H32977 EST108553 cDNA 3159 ± 74  2640 ± 85  2698 ± 66  −1.17 0.0001 AA874887 UI-R-E0-ci-g-10-0-UI.s1 cDNA 459 ± 43 284 ± 23 316 ± 11 −1.45 0.0004 AA850781 EST193549 cDNA 1886 ± 54  1570 ± 55  1602 ± 49  −1.18 0.0004 Increased with Age Correlated with both OMT and SWM AI176456 ESTs, Weakly similar to endothelial actin-binding 8156 ± 447 9404 ± 462 12460 ± 511  1.53 0.0000 protein H31418 EST105434 cDNA 1176 ± 92  1530 ± 66  1904 ± 83  1.62 0.0000 AA858588 ESTs, Weakly similar to dihydrolipoamide acetyl 2740 ± 80  2824 ± 86  3466 ± 198 1.26 0.0014 transferase AA891785 EST195588 cDNA 1140 ± 122 1299 ± 82  1675 ± 89  1.47 0.0021 AA799803 ESTs, Weakly similar to K1CU cytoskeletal keratin 149 ± 35 227 ± 28 297 ± 20 1.99 0.0035 (type 1) AA799449 EST, Weakly similar to ubiquitin carboxyl-terminal −80 ± 7   −2 ± 26  17 ± 19 1.00 0.0044 hydrolase 4 Correlated with OMT AA859777 UI-R-E0-bu-e-10-0-UI.s1 cDNA 1001 ± 43  1396 ± 76  1437 ± 87  1.44 0.0004 AI639532 mixed-tissue library cDNA clone rx01030 3 209 ± 16 282 ± 18 317 ± 22 1.52 0.0018 AA875059 UI-R-E0-cb-f-04-0-UI.s1 cDNA 233 ± 20 219 ± 12 297 ± 14 1.28 0.0023 AI012051 EST206502 cDNA 786 ± 68 987 ± 58 1200 ± 101 1.53 0.0042 AA800549 EST190046 cDNA 3647 ± 121 4078 ± 223 4573 ± 231 1.25 0.0132 Correlated with SWM AA799854 EST189351 cDNA 211 ± 49 328 ± 46 487 ± 60 2.31 0.0037 AA892520 EST196323 cDNA 834 ± 38 826 ± 29 960 ± 36 1.15 0.0152 AA893607 EST197410 cDNA  −9 ± 19  69 ± 20 122 ± 22 1.99 0.0006 AI639381 mixed-tissue library cDNA clone rx01495 3 1531 ± 148 2417 ± 152 2353 ± 189 1.54 0.0013

TABLE 3 Genes and ESTs with Significant Age-Dependent Changes in Expression Level (ANOVA; p ≦ .05) That Did Not Appear in TABLES 1 and 2 GenBank Descriptions Young Mid Age FC ANOVA p Genes, Decreased Correlate with both OMT and SWM M93273 somatostatin receptor subtype 2 1338 ± 142 1395 ± 105 1016 ± 30  −1.32 0.0252 AI175973 ESTs, Highly similar to NADH dehydrogenase 157 ± 18 136 ± 16  95 ± 14 −1.64 0.0314 AA799724 ESTs, Highly similar to DNA-directed RNA 2375 ± 47  2384 ± 79  2120 ± 91  −1.12 0.0321 polymeraseI X06769 FBJ v-fos oncogene homolog 1672 ± 156 1340 ± 154 1145 ± 79  −1.46 0.0329 X89696 TPCR06 protein 763 ± 50 625 ± 38 620 ± 35 −1.23 0.0361 D29766 v-crk-associated tyrosine kinase substrate 2478 ± 129 1929 ± 256 1568 ± 269 −1.58 0.0362 AI102839 cerebellar Ca-binding protein, spot 35 protein 2552 ± 110 2321 ± 131 2088 ± 110 −1.22 0.0364 M80550 adenylyl cyclase 6464 ± 207 6010 ± 212 5752 ± 133 −1.12 0.0403 U18771 Ras-related protein Rab-26 2631 ± 67  2373 ± 101 2350 ± 66  −1.12 0.0410 M36453 Inhibin, alpha 1438 ± 74  1350 ± 73  1178 ± 64  −1.22 0.0449 Correlate with OMT AF055477 L-type voltage-dependent Ca²⁺ channel (α1D 2917 ± 144 2688 ± 119 2449 ± 74  −1.19 0.0275 subunit) AI013627 defender against cell death 1 10148 ± 175  9237 ± 310 9312 ± 219 −1.09 0.0289 AA891916 membrane interacting protein of RGS16 4586 ± 148 4330 ± 114 4117 ± 81  −1.11 0.0295 X67805 Synaptonemal complex protein 1 242 ± 22 189 ± 28 145 ± 23 −1.67 0.0319 D10874 lysosomal vacuolar proton pump (16 kDa) 23958 ± 745  21491 ± 849  21100 ± 812  −1.14 0.0436 D45247 proteasome subunit RCX 13926 ± 267  13333 ± 391  12526 ± 432  −1.11 0.0477 AF040954 putative protein phosphatase1 nuclear targeting 1258 ± 27  1173 ± 35  1149 ± 28  −1.09 0.0515 subunit Correlate with SWM D10262 choline kinase 1248 ± 62  1092 ± 44  1079 ± 33  −1.16 0.0345 AI178921 Insulin degrading enzyme 174 ± 24 163 ± 9  111 ± 17 −1.56 0.0376 L29573 neurotransmitter transporter, noradrenalin 455 ± 47 342 ± 23 344 ± 31 −1.32 0.0475 No significant behavioral correlations U75405 procollagen, type I, alpha 1 490 ± 18 378 ± 34 346 ± 22 −1.42 0.0017 L26292 Kruppel-like factor 4 (gut) 173 ± 21 100 ± 13  95 ± 10 −1.83 0.0018 AI169265 Atp6s1 18405 ± 380  16537 ± 447  16547 ± 318  −1.11 0.0027 L13202 RATHFH2 HNF-3/fork-head homolog-2 (HFH-2) 799 ± 63 557 ± 71 512 ± 19 −1.56 0.0027 AA799779 acyl-CoA: dihydroxyacetonephosphate 2742 ± 82  2363 ± 122 2181 ± 100 −1.26 0.0030 acyltransferase D89340 dipeptidylpeptidase III 2158 ± 76  1824 ± 68  1848 ± 64  −1.17 0.0038 AF019974 Chromogranin B, parathyroid secretory protein 10172 ± 290  8502 ± 400 8604 ± 334 −1.18 0.0038 U72620 Lot1 760 ± 52 620 ± 54 511 ± 35 −1.49 0.0042 U17254 immediate early gene transcription factor NGFI-B 3291 ± 202 2559 ± 115 2496 ± 180 −1.32 0.0045 M83745 Protein convertase subtilisin/kexin, type I 815 ± 43 630 ± 58 578 ± 39 −1.41 0.0048 AA893708 KIAA0560 2575 ± 62  2328 ± 84  2203 ± 74  −1.17 0.0061 H33725 associated molecule with the SH3 domain of STAM 1102 ± 26  970 ± 32 943 ± 41 −1.17 0.0064 AI230914 farnesyltransferase beta subunit 4044 ± 97  3465 ± 130 3498 ± 148 −1.16 0.0065 D37951 MIBP1 (c-myc intron binding protein 1) 6374 ± 194 5826 ± 173 5601 ± 100 −1.14 0.0067 AF076183 cytosolic sorting protein PACS-1a (PACS-1) 5098 ± 314 4039 ± 263 3774 ± 269 −1.35 0.0072 X82445 nuclear distribution gene C homolog (Aspergillus) 3311 ± 111 2910 ± 85  2901 ± 87  −1.14 0.0072 AA800948 Tuba4 8512 ± 215 7857 ± 402 6875 ± 342 −1.24 0.0076 D10699 ubiquitin carboxy-terminal hydrolase L1 19927 ± 1108 16996 ± 631  16532 ± 478  −1.21 0.0090 X57281 Glycine receptor alpha 2 subunit 199 ± 28 118 ± 19 111 ± 13 −1.79 0.0096 X76985 latexin 3937 ± 114 3187 ± 165 3332 ± 201 −1.18 0.0105 X84039 lumican 398 ± 30 283 ± 15 281 ± 36 −1.42 0.0109 U89905 alpha-methylacyl-CoA racemase 927 ± 39 793 ± 33 793 ± 27 −1.17 0.0110 M24852 Neuron specific protein PEP-19 6759 ± 349 5578 ± 280 5483 ± 310 −1.23 0.0146 (Purkinje cell protein 4) U75917 clathrin-associated protein 17 6585 ± 232 5368 ± 330 5557 ± 291 −1.18 0.0158 X53427 glycogen synthase kinase 3 alpha (EC 2.7.1.37) 9799 ± 148 8843 ± 366 8572 ± 281 −1.14 0.0161 U28938 receptor-type protein tyrosine phosphatase D30 1564 ± 91  1354 ± 50  1286 ± 51  −1.22 0.0163 AA891880 Loc65042 2931 ± 59  2607 ± 85  2607 ± 98  −1.12 0.0171 AI232268 LDL receptor-related protein associated protein 1 1708 ± 68  1504 ± 59  1493 ± 36  −1.14 0.0186 AI045249 heat shock 70 kD protein 8 537 ± 42 467 ± 46 366 ± 29 −1.47 0.0195 AF095927 protein phosphatase 2C 2968 ± 120 2516 ± 91  2549 ± 132 −1.16 0.0197 AA819708 Cox7a3 18590 ± 404  17401 ± 452  16742 ± 433  −1.11 0.0201 AA866257 ESTs 4750 ± 198 3994 ± 261 4021 ± 99  −1.18 0.0205 AA942685 cytosolic cysteine dioxygenase 1 9391 ± 397 8145 ± 443 7797 ± 325 −1.20 0.0221 D16478 mitochondrial long-chain enoyl-CoA hydratase 3913 ± 78  3615 ± 95  3499 ± 118 −1.12 0.0222 D88586 eosinophil cationic protein 2522 ± 108 2236 ± 206 1853 ± 138 −1.36 0.0226 E03229 cytosolic cysteine dioxygenase 1 5634 ± 433 4518 ± 512 3918 ± 238 −1.44 0.0227 AB006451 Tim23 5968 ± 155 5562 ± 198 5315 ± 100 −1.12 0.0241 M10068 NADPH-cytochrome P-450 oxidoreductase 5771 ± 205 4998 ± 190 5139 ± 191 −1.12 0.0242 Z48225 protein synthesis initiation factor eIF-2B delta 2710 ± 114 2415 ± 96  2327 ± 78  −1.16 0.0260 subunit M93669 Secretogranin II 4917 ± 225 4395 ± 136 4309 ± 105 −1.14 0.0266 U17254 immediate early gene transcription factor NGFI-B 6004 ± 635 4395 ± 228 4694 ± 316 −1.28 0.0269 U38801 DNA polymerase beta 1173 ± 61  1001 ± 45  997 ± 39 −1.18 0.0270 AA874874 ESTs, Highly similar to alcohol dehydrogenase class 3683 ± 64  3429 ± 83  3436 ± 60  −1.07 0.0278 III AB016532 period homolog 2 (Drosophila) 1440 ± 117 1116 ± 84  1135 ± 62  −1.27 0.0290 AF007758 synuclein, alpha 17737 ± 473  15958 ± 751  15463 ± 459  −1.15 0.0295 U04738 Somatostatin receptor subtype 4 2066 ± 109 1680 ± 70  1733 ± 122 −1.19 0.0300 AF007890 resection-induced TPI (rs11) 513 ± 48 388 ± 43 326 ± 50 −1.58 0.0307 AA874969 ESTs, Highly similar to c-Jun leucine zipper 8555 ± 211 7333 ± 326 7531 ± 387 −1.14 0.0310 interactive M31174 thyroid hormone receptor alpha 16273 ± 775  14217 ± 473  14395 ± 419  −1.13 0.0312 AA801286 Inositol (myo)-1 (or 4)-monophosphatase 1 4767 ± 151 4270 ± 199 4155 ± 118 −1.15 0.0312 AF007554 Mucin1 385 ± 29 276 ± 35 282 ± 26 −1.37 0.0316 X98399 solute carrier family 14, member 1 2002 ± 105 1555 ± 95  1615 ± 151 −1.24 0.0329 AI168942 branched chain keto acid dehydrogenase E1 1580 ± 73  1367 ± 58  1418 ± 30  −1.11 0.0334 AF023087 Early growth response 1 20068 ± 1720 16426 ± 661  16294 ± 622  −1.23 0.0339 K02248 Somatostatin 4314 ± 165 3565 ± 189 3651 ± 245 −1.18 0.0341 AA859954 Vacuole Membrane Protein 1 4197 ± 122 3755 ± 119 3789 ± 128 −1.11 0.0346 AI176621 iron-responsive element-binding protein 1505 ± 66  1334 ± 63  1287 ± 42  −1.17 0.0348 AI010110 SH3-domain GRB2-like 1 1981 ± 67  1596 ± 113 1669 ± 117 −1.19 0.0363 L42855 transcription elongation factor B (SIII) polypeptide 2 10836 ± 201  9654 ± 417 9859 ± 283 −1.10 0.0368 AI136891 zinc finger protein 36, C3H type-like 1 3892 ± 153 3427 ± 188 3247 ± 160 −1.20 0.0369 S77492 Bone morphogenetic protein 3 123 ± 15 103 ± 17  65 ± 14 −1.89 0.0374 AI230778 ESTs, Highly similar to protein-tyrosine sulfotrans. 2 2049 ± 41  2019 ± 120 1714 ± 101 −1.20 0.0380 AA859980 T-complex 1 1710 ± 77  1411 ± 71  1478 ± 90  −1.16 0.0383 U27518 UDP-glucuronosyltransferase 316 ± 22 266 ± 26 223 ± 24 −1.42 0.0394 AF030088 RuvB-like protein 1  497 ± 151 252 ± 39 181 ± 21 −2.74 0.0398 AF013144 MAP-kinase phosphatase (cpg21) 1551 ± 185 1100 ± 98  1149 ± 92  −1.35 0.0408 M58404 thymosin, beta 10 20359 ± 853  18136 ± 773  17948 ± 400  −1.13 0.0413 AA819500 ESTs, Highly similar to AC12_HUMAN 37 kD 532 ± 44 434 ± 30 411 ± 26 −1.29 0.0417 subunit AF020046 integrin alpha E1, epithelial-associated 113 ± 17 109 ± 12  70 ± 10 −1.62 0.0419 D10854 aldehyde reductase 18091 ± 526  16744 ± 433  16538 ± 354  −1.09 0.0422 AF000899 p58/p45, nucleolin 1666 ± 114 1381 ± 81  1359 ± 73  −1.23 0.0430 S77858 non-muscle myosin alkali light chain 10848 ± 292  9865 ± 409 9642 ± 278 −1.12 0.0435 J05031 Isovaleryl Coenzyme A dehydrogenase 1996 ± 57  1799 ± 75  1792 ± 45  −1.11 0.0451 J02773 heart fatty acid binding protein 2242 ± 88  1918 ± 118 1885 ± 99  −1.19 0.0453 AA891041 jun B proto-oncogene 1125 ± 128 788 ± 79 871 ± 68 −1.29 0.0453 AA817887 profilin 12549 ± 398  10859 ± 592  10886 ± 498  −1.15 0.0460 U38379 Gamma-glutamyl hydrolase 2340 ± 215 2136 ± 177 1693 ± 141 −1.38 0.0467 D78308 calreticulin 8256 ± 349 7233 ± 343 7446 ± 126 −1.11 0.0486 AA818487 cyclophilin B 8861 ± 410 7912 ± 293 7779 ± 236 −1.14 0.0488 AA799479 ESTs, Highly similar to NADH-ubiquinone 4937 ± 203 4124 ± 291 4075 ± 263 −1.21 0.0496 oxidoreduct. AI104388 heat shock 27 kD protein 1 2102 ± 72  2072 ± 81  1839 ± 82  −1.14 0.0511 X59737 ubiquitous mitochondrial creatine kinase 11016 ± 315  9658 ± 360 9950 ± 451 −1.11 0.0512 D83948 adult liver S1-1 protein 1411 ± 45  1249 ± 78  1221 ± 30  −1.16 0.0522 AA893788 ESTs, Highly similar to chromobox protein homolog 5 658 ± 33 562 ± 23 568 ± 31 −1.16 0.0541 Genes, Increased Correlate with both OMT and SWM AI230247 selenoprotein P, plasma, 1 7467 ± 279 8179 ± 312 8700 ± 319 1.17 0.0304 AF016269 kallikrein 6 (neurosin, zyme) 1141 ± 75  1166 ± 51  1375 ± 72  1.21 0.0353 AF021935 Ser-Thr protein kinase   2 ± 111  453 ± 193  649 ± 184 10.63 0.0395 M24104 synaptobrevin 2 1145 ± 55  1783 ± 260 1794 ± 210 1.57 0.0544 Correlate with OMT AI235344 geranylgeranyltransferase type I (GGTase-I) 336 ± 21 362 ± 16 413 ± 21 1.23 0.0310 X60212 ASI homolog of bacterial ribosomal subunit protein 17230 ± 994  18514 ± 1115 21606 ± 1305 1.25 0.0365 L22 U14950 tumor suppressor homolog (synapse associ. protein) 315 ± 29 507 ± 61 498 ± 64 1.58 0.0379 X53504 ribosomal protein L12 9290 ± 179 9922 ± 247 10210 ± 290  1.10 0.0448 AA955388 Na⁺K⁺ transporting ATPase 2, beta polypeptide 2 2361 ± 155 2863 ± 320 3237 ± 170 1.37 0.0451 X76489 CD9 cell surface glycoprotein 2485 ± 199 2713 ± 135 3106 ± 170 1.25 0.0467 D28110 myelin-associated oligodendrocytic basic protein 5947 ± 490 7855 ± 539  8814 ± 1109 1.48 0.0499 Correlate with SWM U10357 pyruvate dehydrogenase kinase 2 subunit p45 3565 ± 133 3921 ± 274 4485 ± 240 1.26 0.0292 (PDK2) D00569 2,4-dienoyl CoA reductase 1, mitochondrial 200 ± 22 241 ± 32 307 ± 24 1.54 0.0293 AA818240 Nuclear pore complex protein 308 ± 35 440 ± 42 424 ± 28 1.38 0.0329 M24104 synaptobrevin 2  685 ± 193 1379 ± 247 1581 ± 250 2.31 0.0332 D28557 cold shock domain protein A 1383 ± 89  1491 ± 129 1803 ± 106 1.30 0.0337 X54467 cathepsin D 3715 ± 294 4091 ± 388 5138 ± 431 1.38 0.0373 X13905 ras-related rab1B protein  201 ± 111  803 ± 179  689 ± 181 3.43 0.0388 AI228548 ESTs, Highly similar to DKFZp586G0322.1 1909 ± 140 2053 ± 75  2321 ± 110 1.22 0.0412 V01244 Prolactin  75 ± 37  70 ± 37  354 ± 140 4.75 0.0476 L24896 glutathione peroxidase 4 12303 ± 650  12725 ± 456  14045 ± 358  1.14 0.0479 No significant behavioral correlations U77777 interleukin 18 252 ± 15 290 ± 12 371 ± 32 1.47 0.0025 AI102299 Bid3 267 ± 98 527 ± 59 603 ± 21 2.26 0.0032 L19998 Phenol-preferring sulfotransferase 1A 373 ± 36 507 ± 27 616 ± 69 1.65 0.0065 AF051561 solute carrier family 12, member 2 2749 ± 82  3228 ± 83  3281 ± 163 1.19 0.0074 U08259 Glutamate receptor, N-methyl D-aspartate 2C 919 ± 34 989 ± 49 1118 ± 38  1.22 0.0074 AB008538 HB2 3733 ± 133 4436 ± 189 4264 ± 117 1.14 0.0087 AF016296 neuropilin 1838 ± 121 2279 ± 85  2259 ± 110 1.23 0.0111 X62950 pBUS30 with repetitive elements 360 ± 25 577 ± 67 548 ± 47 1.52 0.0124 AF030050 replication factor C 857 ± 62 1154 ± 73  1148 ± 81  1.34 0.0127 AA848831 lysophosphatidic acid G-protein-coupled receptor, 2 1854 ± 170 2729 ± 225 2784 ± 261 1.50 0.0129 M91234 VL30 element 2573 ± 152 3409 ± 221 3467 ± 254 1.35 0.0134 J05132 UDP-glucuronosyltransferase 968 ± 76 1283 ± 68  1212 ± 74  1.25 0.0148 AF008554 implantation-associated protein (IAG2) 362 ± 46 528 ± 33 500 ± 40 1.38 0.0162 AI231807 ferritin light chain 1 5496 ± 174 5863 ± 273 6469 ± 197 1.18 0.0163 S72594 tissue inhibitor of metalloproteinase 2 3615 ± 205 4386 ± 216 4227 ± 114 1.17 0.0170 S61868 Ryudocan/syndecan 4 6117 ± 292 6315 ± 211 7348 ± 385 1.20 0.0182 X06916 S100 calcium-binding protein A4 572 ± 40 630 ± 60 868 ± 99 1.52 0.0184 U67136 A kinase (PRKA) anchor protein 5 306 ± 59 531 ± 66 551 ± 61 1.80 0.0191 Y17295 thiol-specific antioxidant protein (1-Cys 2414 ± 154 3037 ± 133 2998 ± 193 1.24 0.0221 peroxiredoxin) D45249 protease (prosome, macropain) 28 subunit, alpha 4169 ± 119 4657 ± 205 4808 ± 121 1.15 0.0223 U67137 guanylate kinase associated protein 3198 ± 366 4262 ± 333 4338 ± 177 1.36 0.0229 AF074608 MHC class I antigen (RT1.EC2) gene  782 ± 129  940 ± 110 1213 ± 69  1.55 0.0231 U67080 r-MyT13 −29 ± 17  74 ± 38  92 ± 32 1.50 0.0250 AI013861 3-hydroxyisobutyrate dehydrogenase 3347 ± 136 3759 ± 101 3678 ± 73  1.10 0.0255 S53527 S100 calcium-binding protein, beta (neural) 25683 ± 925  25830 ± 765  29195 ± 1184 1.14 0.0266 D89730 Fibulin 3, fibulin-like extracellular matrix protein 1 239 ± 23 351 ± 52 424 ± 50 1.78 0.0271 D90211 Lysosomal-associated membrane protein 2 3095 ± 142 3577 ± 157 3715 ± 168 1.20 0.0276 AA859645 attractin 2647 ± 81  2871 ± 82  2942 ± 60  1.11 0.0278 X55153 ribosomal protein P2 18829 ± 779  19676 ± 485  21368 ± 641  1.13 0.0284 M55015 nucleolin 6685 ± 139 6738 ± 263 7385 ± 147 1.10 0.0297 L25605 Dynamin 2 759 ± 84 780 ± 71 1109 ± 129 1.46 0.0303 AI231807 ferritin light chain 1 9399 ± 508 10459 ± 538  11268 ± 329  1.20 0.0312 L00191 Fibronectin 1 395 ± 23 530 ± 44 557 ± 53 1.41 0.0316 D28110 myelin-associated oligodendrocytic basic protein  837 ± 127 1177 ± 106 1331 ± 141 1.59 0.0320 AI176595 Cathepsin L 2414 ± 73  2639 ± 57  2678 ± 80  1.11 0.0324 X14323 Fc receptor, IgG, alpha chain transporter 431 ± 38 510 ± 71 640 ± 42 1.49 0.0328 X74226 LL5 protein 2042 ± 69  2000 ± 66  2279 ± 92  1.12 0.0330 AA892775 Lysozyme 1760 ± 88  1781 ± 65  2438 ± 314 1.39 0.0337 X02904 glutathione S-transferase P subunit 2861 ± 124 3514 ± 276 3570 ± 141 1.25 0.0339 AI012589 glutathione S-transferase, pi 2 6325 ± 340 7706 ± 465 7807 ± 418 1.23 0.0353 AB000778 Phoshpolipase D gene 1 194 ± 24 270 ± 18 287 ± 31 1.48 0.0374 X97443 integral membrane protein Tmp21-I (p23) 862 ± 64 1194 ± 131 1211 ± 90  1.40 0.0396 X58294 carbonic anhydrase 2 5372 ± 252 6554 ± 399 6347 ± 290 1.18 0.0398 M99485 Myelin oligodendrocyte glycoprotein 2546 ± 107 2645 ± 113 3176 ± 259 1.25 0.0405 M23601 Monoamine oxidase B 4962 ± 268 5244 ± 152 5763 ± 212 1.16 0.0406 J05022 peptidylarginine deiminase 3834 ± 133 4231 ± 137 4503 ± 231 1.17 0.0425 Z49858 plasmolipin 2111 ± 146 2437 ± 69  2624 ± 172 1.24 0.0429 D17309 delta 4-3-ketosteroid-5-beta-reductase 568 ± 66 930 ± 96  951 ± 150 1.67 0.0432 AA955306 ras-related protein rab10 3912 ± 289 4796 ± 339 4975 ± 257 1.27 0.0444 M19936 Prosaposin-sphingolipid hydrolase activator 12981 ± 997  14182 ± 780  16095 ± 751  1.24 0.0463 M57276 Leukocyte antigen (Ox-44) 879 ± 79 1071 ± 65  1117 ± 57  1.27 0.0469 J02752 acyl-coA oxidase 1853 ± 119 2187 ± 155 2344 ± 118 1.26 0.0470 U78517 cAMP-regulated guanine nucleotide exchange 3400 ± 134 3956 ± 216 3903 ± 113 1.15 0.0477 factor II AI102031 myc box dependent interacting protein 1 6381 ± 242 6919 ± 237 7265 ± 236 1.14 0.0486 M89646 ribosomal protein S24 14041 ± 448  15044 ± 319  15482 ± 416  1.10 0.0491 AA924925 ER transmembrane protein Dri 42  435 ± 209  799 ± 143 1067 ± 160 2.45 0.0493 X16933 RNA binding protein p45AUF1 1516 ± 166 2186 ± 203 2139 ± 221 1.41 0.0499 X72757 cox VIa gene (liver) 666 ± 73 855 ± 39 829 ± 51 1.24 0.0502 AA957132 N-acetylglucosaminyltransferase I 242 ± 26 401 ± 56 398 ± 54 1.64 0.0508 AA818025 CD59 antigen 5668 ± 298 6175 ± 280 6909 ± 414 1.22 0.0509 AI237007 ESTs, Highly similar to flavoprotf.-ubiquin.  48 ± 37 117 ± 50 195 ± 29 3.19 0.0519 Oxidoreduct. U07619 Coagulation factor III (thromboplastin, tissue factor) 701 ± 37 792 ± 37 847 ± 46 1.21 0.0544 ESTs, Decreased Correlate with both OMT and SWM AA874830 UI-R-E0-cg-f-04-0-UI.s1 cDNA 1584 ± 87  1406 ± 65  1323 ± 33  −1.20 0.0268 AA875032 UI-R-E0-cb-h-09-0-UI.s1 cDNA 1770 ± 40  1536 ± 91  1490 ± 72  −1.19 0.0288 AA799599 EST189096 cDNA 6628 ± 210 6184 ± 281 5618 ± 257 −1.18 0.0328 AA892813 EST196616 cDNA 218 ± 41 241 ± 54  92 ± 25 −2.37 0.0363 AA799529 EST189026 cDNA 1590 ± 61  1529 ± 51  1388 ± 55  −1.15 0.0466 AA893584 EST197387 cDNA 4021 ± 120 3570 ± 206 3416 ± 167 −1.18 0.0548 Correlate with OMT AA894305 EST198108 cDNA 4779 ± 107 4393 ± 138 4261 ± 151 −1.12 0.0349 AA800622 EST190119 cDNA 2372 ± 76  2325 ± 102 2056 ± 83  −1.15 0.0370 AA893690 EST197493 cDNA 5102 ± 229 4813 ± 146 4334 ± 220 −1.18 0.0378 AA891221 EST195024 cDNA 4562 ± 179 4159 ± 173 3956 ± 128 −1.15 0.0423 AA893320 EST197123 cDNA 1110 ± 35  1071 ± 69  911 ± 57 −1.22 0.0455 AA891537 EST195340 cDNA 2420 ± 94  2098 ± 85  2145 ± 96  −1.13 0.0468 AA799680 EST189177 cDNA 560 ± 45 544 ± 33 431 ± 39 −1.30 0.0504 Correlate with SWM AA893199 EST197002 cDNA 2422 ± 100 2482 ± 67  2129 ± 112 −1.14 0.0287 AA799636 EST189133 cDNA 3279 ± 92  2986 ± 125 2826 ± 124 −1.16 0.0358 AA874995 UI-R-E0-cf-d-08-0-UI.s1 cDNA 1202 ± 44  1123 ± 37  1068 ± 19  −1.13 0.0360 AA892298 EST196101 cDNA 302 ± 26 243 ± 13 229 ± 22 −1.32 0.0456 AA892538 EST196341 cDNA 1033 ± 64  902 ± 41 868 ± 36 −1.19 0.0547 No significant behavioral correlations AA859690 UI-R-E0-bx-e-11-0-UI.s1 cDNA 297 ± 29 173 ± 40 137 ± 10 −2.17 0.0017 AA875004 UI-R-E0-cb-b-07-0-UI.s1 cDNA 965 ± 40 774 ± 44 776 ± 30 −1.24 0.0022 AA891037 EST194840 cDNA 2174 ± 98  1781 ± 83  1774 ± 68  −1.23 0.0031 AA893185 EST196988 cDNA 7616 ± 301 6680 ± 137 6666 ± 166 −1.14 0.0045 AA892511 EST196314 cDNA 4716 ± 113 4061 ± 150 4216 ± 139 −1.12 0.0068 AA875129 UI-R-E0-bu-e-01-0-UI.s2 cDNA 1214 ± 28  1093 ± 33  1062 ± 34  −1.14 0.0071 AA800693 EST190190 cDNA 3177 ± 84  2844 ± 82  2830 ± 71  −1.12 0.0072 AA859562 UI-R-E0-bv-b-03-0-UI.s1 cDNA 933 ± 91 682 ± 57 606 ± 58 −1.54 0.0078 AA860030 UI-R-E0-bz-e-07-0-UI.s2 cDNA 20727 ± 774  17601 ± 811  17941 ± 508  −1.16 0.0090 AA891727 EST195530 cDNA 5801 ± 266 4821 ± 204 5038 ± 189 −1.15 0.0114 AA892796 EST196599 cDNA 6952 ± 143 6326 ± 167 6441 ± 110 −1.08 0.0117 AI639477 mixed-tissue library cDNA clone rx02351 3 264 ± 26 193 ± 53  78 ± 40 −3.39 0.0154 AA893717 EST197520 cDNA 515 ± 24 442 ± 35 386 ± 27 −1.33 0.0179 AA892414 EST196217 cDNA 2935 ± 143 2507 ± 111 2511 ± 79  −1.17 0.0185 AA893743 EST197546 cDNA 2730 ± 120 2282 ± 121 2181 ± 154 −1.25 0.0193 AI176491 EST220076 cDNA 5180 ± 182 4665 ± 213 4450 ± 108 −1.16 0.0199 AA799481 EST188978 cDNA 1036 ± 33  889 ± 31 916 ± 44 −1.13 0.0240 AA859643 UI-R-E0-bs-a-08-0-UI.s1 cDNA 4772 ± 162 3978 ± 177 4165 ± 238 −1.15 0.0252 AA875257 UI-R-E0-cq-d-12-0-UI.s1 cDNA 1715 ± 133 1369 ± 92  1342 ± 71  −1.28 0.0255 AA685974 EST108806 cDNA 5543 ± 142 4855 ± 194 4974 ± 184 −1.11 0.0275 AA891476 EST195279 cDNA 7512 ± 289 7075 ± 235 6520 ± 208 −1.15 0.0279 AA891950 EST195753 cDNA 865 ± 18 818 ± 45 725 ± 33 −1.19 0.0284 AA875019 UI-R-E0-cb-f-08-0-UI.s1 cDNA 1007 ± 32  908 ± 29 901 ± 29 −1.12 0.0357 AA866477 UI-R-E0-br-h-03-0-UI.s1 cDNA 11037 ± 230  9932 ± 341 10208 ± 283  −1.08 0.0376 AI639209 mixed-tissue library cDNA clone rx00680 3 763 ± 57 820 ± 98 562 ± 44 −1.36 0.0385 AI102868 EST212157 cDNA 11364 ± 316  9876 ± 516 9787 ± 490 −1.16 0.0418 AI178204 EST221869 cDNA 2465 ± 180 2162 ± 137 1905 ± 122 −1.29 0.0419 AA799858 EST189355 cDNA 1068 ± 76  925 ± 58 827 ± 58 −1.29 0.0427 AA800026 EST189523 cDNA 249 ± 29 155 ± 26 144 ± 35 −1.73 0.0429 AA892637 EST196440 cDNA 809 ± 16 757 ± 24 739 ± 16 −1.10 0.0430 AA859545 ESTs, Weakly similar to hypothetical protein 3289 ± 167 2762 ± 137 2876 ± 134 −1.14 0.0442 C09H6.3 AA859848 UI-R-E0-cc-h-10-0-UI.s1 cDNA 3396 ± 315 3150 ± 165 2626 ± 129 −1.29 0.0456 H33086 EST108750 cDNA 21205 ± 763  18706 ± 530  19138 ± 810  −1.11 0.0477 AA893224 EST197027 cDNA 2325 ± 67  2150 ± 75  2076 ± 64  −1.12 0.0502 ESTs, Increased Correlate with both OMT and SWM AA893946 EST197749 cDNA 371 ± 45 565 ± 43 544 ± 72 1.47 0.0440 Correlate with OMT AI638997 mixed-tissue library cDNA clone rx05048 3 402 ± 23 450 ± 26 483 ± 11 1.20 0.0381 AI177404 EST221024 cDNA 1012 ± 46  1193 ± 73  1245 ± 65  1.23 0.0429 Correlate with SWM AA800318 EST189815 cDNA 315 ± 46 376 ± 40 474 ± 41 1.51 0.0421 No significant behavioral correlations AA893082 EST196885 cDNA 1454 ± 95  1902 ± 43  1865 ± 110 1.28 0.0021 AA892986 EST196789 cDNA 586 ± 19 627 ± 33 756 ± 39 1.29 0.0025 M13100 long interspersed repetitive DNA sequence LINE3 4328 ± 230 5963 ± 252 5947 ± 457 1.37 0.0026 AA891734 EST195537 cDNA 1648 ± 86  1778 ± 82  2045 ± 60  1.24 0.0037 AI171966 ESTs, Highly similar to selenide, water dikinase 2 880 ± 42 934 ± 30 1181 ± 93  1.34 0.0049 AI639151 mixed-tissue library cDNA clone rx02802 3 939 ± 49 1192 ± 80  1223 ± 54  1.30 0.0083 AA875037 UI-R-E0-cb-a-03-0-UI.s1 cDNA  11 ± 71 268 ± 70 357 ± 78 5.84 0.0084 AA891690 ESTs, Weakly similar to p-serine aminotransferase 1858 ± 76  1955 ± 65  2296 ± 131 1.24 0.0088 AA891810 EST195613 cDNA 1504 ± 140 2028 ± 155 2274 ± 202 1.51 0.0125 AA866432 UI-R-E0-ch-e-06-0-UI.s1 cDNA 2777 ± 150 3380 ± 102 3493 ± 226 1.26 0.0143 X05472 2.4 kb repeat DNA right terminal region 4188 ± 565 5325 ± 564 7241 ± 899 1.73 0.0173 AA892146 EST195949 cDNA 5386 ± 450 7073 ± 436 7004 ± 418 1.30 0.0187 AA852046 EST194815 cDNA 1697 ± 140 2163 ± 92  2051 ± 112 1.21 0.0234 AA799396 EST188893 cDNA 163 ± 26 264 ± 35 269 ± 24 1.65 0.0275 AI638971 mixed-tissue library cDNA clone rx04989 3 128 ± 26 188 ± 13 213 ± 24 1.67 0.0285 AA892520 EST196323 cDNA 479 ± 31 526 ± 28 601 ± 33 1.25 0.0305 AA891774 EST195577 cDNA −518 ± 92  −115 ± 126 −147 ± 108 1.00 0.0322 M13100 long interspersed repetitive DNA sequence LINE3 8845 ± 982 12115 ± 1117 12282 ± 814  1.39 0.0366 AI639257 mixed-tissue library cDNA clone rx01119 3 172 ± 23 306 ± 41 286 ± 41 1.66 0.0386 AA866299 UI-R-A0-ac-f-12-0-UI.s3 cDNA 684 ± 45 810 ± 24 885 ± 73 1.29 0.0390 AA799773 EST189270 cDNA 299 ± 30 408 ± 24 433 ± 50 1.45 0.0407 AA866299 UI-R-A0-ac-f-12-0-UI.s3 cDNA 522 ± 32 623 ± 28 626 ± 31 1.20 0.0415 AA891944 EST195747 cDNA 193 ± 15 198 ± 13 247 ± 20 1.28 0.0488

Using the method of the invention, we have identified a set of genes and ESTs that changed with age by ANOVA (p≦0.05), but which are not ACGs. These include AA685974 (EST108806 cDNA); AA799396 (EST188893 cDNA); AA799479 (ESTs, Highly similar to NADH-ubiquinone oxidoreduct.); AA799481 (EST188978 cDNA); AA799529 (EST189026 cDNA); AA799599 (EST189096 cDNA); AA799636 (EST189133 cDNA); AA799680 (EST189177 cDNA); AA799724 (ESTs, Highly similar to DNA-directed RNA polymerase I); AA799773 (EST 189270 cDNA); AA799779 (acyl-CoA:dihydroxyacetonephosphate acyltransferase); AA799858 (EST189355 cDNA); AA800026 (EST189523 cDNA); AA800318 (EST189815 cDNA); AA800622 (EST190119 cDNA); AA800693 (EST190190 cDNA); AA800948 (Tuba4); AA801286 (Inositol (myo)-1(or 4)-monophosphatase 1); AA817887 (profilin); AA818025 (CD59 antigen); AA818240 (Nuclear pore complex protein); AA818487 (cyclophilin B); AA819500 (ESTs, Highly similar to AC12_HUMAN 37 kD subunit); AA819708 (Cox7a3); AA848831 (lysophosphatidic acid G-protein-coupled receptor, 2); AA852046 (EST194815 cDNA); AA859545 (ESTs, Weakly similar to hypothetical protein C09H6.3); AA859562 (UI-R-E0-bv-b-03-0-UI.s1 cDNA); AA859643 (UI-R-E0-bs-a-08-0-UI.s1 cDNA); AA859645 (attractin); AA859690 (UI-R-E0-bx-e-11-0-UI.s1 cDNA); AA859848 (UI-R-E0-cc-h-10-0-UI.s1 cDNA); AA859954 (Vacuole Membrane Protein 1); AA859980 (T-complex 1); AA860030 (UI-R-E0-bz-e-07-0-UI.s2 cDNA); AA866257 (ESTs); AA866299 (UI-R-A0-ac-f-12-0-UI.s3 cDNA); AA866299 (UI-R-A0-ac-f-12-0-UI.s3 cDNA); AA866432 (UI-R-E0-ch-e-06-0-UI.s1 cDNA); AA866477 (UI-R-E0-br-h-03-0-UI.s1 cDNA); AA874830 (UI-R-E0-cg-f-04-0-UI.s1 cDNA); AA874874 (ESTs, Highly similar to alcohol dehydrogenase class III); AA874969 (ESTs, Highly similar to c-Jun leucine zipper interactive); AA874995 (UI-R-E0-cf-d-08-0-UI.s1 cDNA); AA875004 (UI-R-E0-cb-b-07-0-UI.s1 cDNA); AA875019 (UI-R-E0-cb-f-08-0-UI.s1 cDNA); AA875032 (UI-R-E0-cb-h-09-0-UI.s1 cDNA); AA875037 (UI-R-E0-cb-a-03-0-UI.s1 cDNA); AA875129 (UI-R-E0-bu-e-01-0-UI.s2 cDNA); AA875257 (UI-R-E0-cq-d-12-0-UI.s1 cDNA); AA891037 (EST194840 cDNA); AA891041 (un B proto-oncogene); AA891221 (EST195024 cDNA); AA891476 (EST195279 cDNA); AA891537 (EST195340 cDNA); AA891690 (ESTs, Weakly similar to p-serine aminotransferase); AA891727 (EST195530 cDNA); AA891734 (EST195537 cDNA); AA891774 (EST195577 cDNA); AA891810 (EST195613 cDNA); AA891880 (Loc65042); AA891916 (membrane interacting protein of RGS16); AA891944 (EST195747 cDNA); AA891950 (EST195753 cDNA); AA892146 (EST195949 cDNA); AA892298 (EST196101 cDNA); AA892414 (EST196217 cDNA); AA892511 (EST196314 cDNA); AA892520 (EST196323 cDNA); AA892538 (EST196341 cDNA); AA892637 (EST196440 cDNA); AA892775 (Lysozyme); AA892796 (EST196599 cDNA); AA892813 (EST196616 cDNA); AA892986 (EST196789 cDNA); AA893082 (EST196885 cDNA); AA893185 (EST196988 cDNA); AA893199 (EST197002 cDNA); AA893224 (EST197027 cDNA); AA893320 (EST197123 cDNA); AA893584 (EST197387 cDNA); AA893690 (EST197493 cDNA); AA893708 (KIAA0560); AA893717 (EST197520 cDNA); AA893743 (EST197546 cDNA); AA893788 (ESTs, Highly similar to chromobox protein homolog 5); AA893946 (EST197749 cDNA); AA894305 (EST198108 cDNA); AA924925 (ER transmembrane protein Dri 42); AA942685 (cytosolic cysteine dioxygenase 1); AA955306 (ras-related protein rab10); AA955388 (Na⁺K⁺ transporting ATPase 2, beta polypeptide 2); AA957132 (N-acetylglucosaminyltransferase I); AB000778 (Phoshpolipase D gene 1); AB006451 (Tim23); AB008538 (HB2); AB016532 (period homolog 2 (Drosophila)); AF000899 (p58/p45, nucleolin); AF007554 (Mucin1); AF007758 (synuclein, alpha); AF007890 (resection-induced TPI (rs11)); AF008554 (implantation-associated protein (IAG2)); AF013144 (MAP-kinase phosphatase (cpg21)); AF016269 (kallikrein 6 (neurosin, zyme)); AF016296 (neuropilin); AF019974 (Chromogranin B, parathyroid secretory protein); AF020046 (integrin alpha E1, epithelial-associated); AF021935 (Ser-Thr protein kinase); AF023087 (Early growth response 1); AF030050 (replication factor C); AF030088 (RuvB-like protein 1); AF040954 (putative protein phosphatase 1 nuclear targeting subunit); AF051561 (solute carrier family 12, member 2); AF055477 (L-type voltage-dependent Ca²⁺ channel (?1D subunit)); AF074608 (MHC class I antigen (RT1.EC2) gene); AF076183 (cytosolic sorting protein PACS-1a (PACS-1)); AF095927 (protein phosphatase 2C); AI010110 (SH3-domain GRB2-like 1); AI012589 (glutathione S-transferase, pi 2); AI013627 (defender against cell death 1); AI013861 (3-hydroxyisobutyrate dehydrogenase); AI045249 (heat shock 70 kD protein 8); AI102031 (myc box dependent interacting protein 1); AI102299 (Bid3); AI102839 (cerebellar Ca-binding protein, spot 35 protein); AI102868 (EST212157 cDNA); AI104388 (heat shock 27 kD protein 1); AI136891 (zinc finger protein 36, C3H type-like 1); AI168942 (branched chain keto acid dehydrogenase E1); AI169265 (Atp6s1); AI171966 (ESTs, Highly similar to selenide, water dikinase 2); AI175973 (ESTs, Highly similar to NADH dehydrogenase); AI176491 (EST220076 cDNA); AI176595 (Cathepsin L); AI176621 (iron-responsive element-binding protein); AI177404 (EST221024 cDNA); AI178204 (EST221869 cDNA); AI178921 (Insulin degrading enzyme); AI228548 (ESTs, Highly similar to DKFZp586G0322.1); AI230247 (selenoprotein P, plasma, 1); AI230778 (ESTs, Highly similar to protein-tyrosine sulfotrans. 2); AI230914 (farnesyltransferase beta subunit); AI231807 (ferritin light chain 1); AI231807 (ferritin light chain 1); AI232268 (LDL receptor-related protein associated protein 1); AI235344 (geranylgeranyltransferase type I (GGTase-I)); AI237007 (ESTs, Highly similar to flavoprot.-ubiquin. Oxidoreduct.); AI638971 (mixed-tissue library cDNA clone rx04989 3); AI638997 (mixed-tissue library cDNA clone rx05048 3); AI639151 (mixed-tissue library cDNA clone rx02802 3); AI639209 (mixed-tissue library cDNA clone rx00680 3); AI639257 (mixed-tissue library cDNA clone rx01119 3); AI639477 (mixed-tissue library cDNA clone rx02351 3); D00569 (2,4-dienoyl CoA reductase 1, mitochondrial); D10262 (choline kinase); D10699 (ubiquitin carboxy-terminal hydrolase L1); D10854 (aldehyde reductase); D10874 (lysosomal vacuolar proton pump (16 kDa)); D16478 (mitochondrial long-chain enoyl-CoA hydratase); D17309 (delta 4-3-ketosteroid-5-beta-reductase); D28110 (myelin-associated oligodendrocytic basic protein); D28110 (myelin-associated oligodendrocytic basic protein); D28557 (cold shock domain protein A); D29766 (v-crk-associated tyrosine kinase substrate); D37951 (MIBP1 (c-myc intron binding protein 1)); D45247 (proteasome subunit RCX); D45249 (protease (prosome, macropain) 28 subunit, alpha); D78308 (calreticulin); D83948 (adult liver S1-1 protein); D88586 (eosinophil cationic protein); D89340 (dipeptidylpeptidase III); D89730 (Fibulin 3, fibulin-like extracellular matrix protein 1); D90211 (Lysosomal-associated membrane protein 2); E03229 (cytosolic cysteine dioxygenase 1); H33086 (EST108750 cDNA); H33725 (associated molecule with the SH3 domain of STAM); J02752 (acyl-coA oxidase); J02773 (heart fatty acid binding protein); J05022 (peptidylarginine deiminase); J05031 (Isovaleryl Coenzyme A dehydrogenase); J05132 (UDP-glucuronosyltransferase); K02248 (Somatostatin); L00191 (Fibronectin 1); L13202 (RATHFH2 HNF-3/fork-head homolog-2 (HFH-2)); L19998 (sulfotransferase family 1A, phenol-preferring, member 1); L24896 (glutathione peroxidase 4); L25605 (Dynamin 2); L26292 (Kruppel-like factor 4 (gut)); L29573 (neurotransmitter transporter, noradrenalin); L42855 (transcription elongation factor B (SIII) polypeptide 2); M10068 (NADPH-cytochrome P-450 oxidoreductase); M13100 (long interspersed repetitive DNA sequence LINE3); M13100 (long interspersed repetitive DNA sequence LINE3); M19936 (Prosaposin-sphingolipid hydrolase activator); M23601 (Monoamine oxidase B); M24104 (synaptobrevin 2); M24104 (Vesicle-associated membrane protein (synaptobrevin 2)); M24852 (Neuron specific protein PEP-19 (Purkinje cell protein 4)); M31174 (thyroid hormone receptor alpha); M36453 (Inhibin, alpha); M55015 (nucleolin); M57276 (Leukocyte antigen (Ox-44)); M58404 (thymosin, beta 10); M80550 (adenylyl cyclase); M83745 (Protein convertase subtilisin/kexin, type I); M89646 (ribosomal protein S24); M91234 (VL30 element); M93273 (somatostatin receptor subtype 2); M93669 (Secretogranin II); M99485 (Myelin oligodendrocyte glycoprotein); S53527 (S100 calcium-binding protein, beta (neural)); S61868 (Ryudocan/syndecan 4); S72594 (tissue inhibitor of metalloproteinase 2); S77492 (Bone morphogenetic protein 3); S77858 (non-muscle myosin alkali light chain); U04738 (Somatostatin receptor subtype 4); U07619 (Coagulation factor III (thromboplastin, tissue factor)); U08259 (Glutamate receptor, N-methyl D-aspartate 2C); U10357 (pyruvate dehydrogenase kinase 2 subunit p45 (PDK2)); U14950 (tumor suppressor homolog (synapse associ. protein)); U17254 (immediate early gene transcription factor NGFI-B); U17254 (immediate early gene transcription factor NGFI-B); U18771 (Ras-related protein Rab-26); U27518 (UDP-glucuronosyltransferase); U28938 (receptor-type protein tyrosine phosphatase D30); U38379 (Gamma-glutamyl hydrolase); U38801 (DNA polymerase beta); U67080 (r-MyT13); U67136 (A kinase (PRKA) anchor protein 5); U67137 (guanylate kinase associated protein); U72620 (Lot1); U75405 (procollagen, type I, alpha 1); U75917 (clathrin-associated protein 17); U77777 (interleukin 18); U78517 (cAMP-regulated guanine nucleotide exchange factor II); U89905 (alpha-methylacyl-CoA racemase); V01244 (Prolactin); X02904 (glutathione S-transferase P subunit); X05472 (2.4 kb repeat DNA right terminal region); X06769 (FBJ v-fos oncogene homolog); X06916 (S100 calcium-binding protein A4); X13905 (ras-related rab1B protein); X14323 (Fc receptor, IgG, alpha chain transporter); X16933 (RNA binding protein p45AUF1); X53427 (glycogen synthase kinase 3 alpha (EC 2.7.1.37)); X53504 (ribosomal protein L12); X54467 (cathepsin D); X55153 (ribosomal protein P2); X57281 (Glycine receptor alpha 2 subunit); X58294 (carbonic anhydrase 2); X59737 (ubiquitous mitochondrial creatine kinase); X60212 (ASI homolog of bacterial ribosomal subunit protein L22); X62950 (pBUS30 with repetitive elements); X67805 (Synaptonemal complex protein 1); X72757 (cox VIa gene (liver)); X74226 (LL5 protein); X76489 (CD9 cell surface glycoprotein); X76985 (latexin); X82445 (nuclear distribution gene C homolog (Aspergillus)); X84039 (lumican); X89696 (TPCR06 protein); X97443 (integral membrane protein Tmp21-I (p23)); X98399 (solute carrier family 14, member 1); Y17295 (thiol-specific antioxidant protein (1-Cys peroxiredoxin)); Z48225 (protein synthesis initiation factor eIF-2B delta subunit); Z49858 (plasmolipin).

Using the method of the invention, we have also identified a set of genes and ESTs that changed with age (p≦0.05), but which are correlated with cognitive performance in behavioral tests. These include L03294 (Lpl, lipoprotein lipase); M18416 (Egr1, Early growth response 1 (Krox-24)); S68245 (Ca4, carbonic anhydrase 4); M64780 (Agrn, Agrin); M27207 (Colla1, Procollagen-type I (alpha 1)); X16554 (Prps1, Phosphoribosyl pyrophosphate synthetase 1); M92433 (NGFI-C, Zinc-finger transcription factor (early response gene)); AA859975 (LOC64201, 2-oxoglutarate carrier); L08595 (Nuclear receptor subfamily 4, group A, member 2); M24542 (RISP, Rieske iron-sulfur protein); AI030089 (Nopp130, nucleolar phosphoprotein p130); AF104362 (Omd, Osteomodulin (osteoadherin)); L46873 (Slc15a1, Oligopeptide transporter); AI176689 (MAPKK 6, mitogen-activated protein kinase kinase 6); U66470 (rCGR11, Cell growth regulator); AF016387 (RXRG, retinoid X-receptor gamma); M18467 (Got2, glutamate oxaloacetate transaminase 2); X54793 (Hsp60, heat shock protein 60); X64401 (Cyp3a3, Cytochrome P450-subfamily 111A (polypeptide 3)); M37584 (H2afz, H2A histone family (member Z)); L21192 (GAP-43, membrane attached signal protein 2 (brain)); AA875047 (TCPZ, T-complex protein 1 (zeta subunit)); U90610 (Cxcr4, CXC chemokine receptor); AF003904 (CRH-binding protein); U83880 (GPDH-M, glycerol-3-phosphate dehydrogenase, mitochondrial); X89703 (TPCR19, Testis Polymerase Chain Reaction product 19); D63886 (MMP16, matrix metalloproteinase 16); J05499 (GLS, glutaminase (mitochondrial)); D21799 (Psmb2, Proteasome subunit (beta type 2)); AA800794 (HT2A, zinc-finger protein); U90887 (Arg2, arginase type II); S82649 (Narp, neuronal activity-regulated pentraxin); M74223 (VGF, neurosecretory protein); AA874794 (Bex3, brain expressed X-linked 3); M15191 (Tac1, Tachykinin); AA892506 (coronin, actin binding protein 1A); L04485 (MAPPK1, mitogen-activated protein kinase kinase 1); AA799641 (S164, Contains a PWI domain associated with RNA splicing); AA817892 (Gnb2, Guanine nucleotide binding protein (beta 2 subunit)); AA893939 (DSS1, deleted in split hand/split foot protein 1); AF000901 (P58/P45, Nucleoporin p58); AF087037 (Btg3, B-cell translocation gene 3); AB000280 (PHT1, peptide/histidine transporter); M87854 (Beta-ARK-1, beta adrenergic receptor kinase 1); U06099 (Prdx2, Peroxiredoxin 2); AF058795 (Gb2, GABA-B receptor); AA800517 (VAP1, vesicle associated protein); U63740 (Fez1, Protein kinase C-binding protein Zeta1); U53922 (Hsj2, DnaJ-like protein (RDJ1)); U78102 (Egr2, Early growth response 2); U44948 (SmLIM, smooth muscle cell LIM protein); U87627 (MCT3, putative monocarboxylate transporter); AB020504 (PMF31, highly homologus to mouse F-box-WD40 repeat protein 6); M21354 (Col3a1, collagen type III alpha-1); AA893664 (Temo, sertoli cell marker (KIAA0077 protein fragment)); AB010437 (CDH8, Cadherin-8); M22756 (Ndufv2, mitochondrial NADH dehydrogenase (24 kDa)); AA799389 (Rab3B, ras-related protein); AI172476 (Tieg-1, TGF-beta-inducible early growth response protein 1); AF091563 (Olfactory receptor); M64376 (Olfactory protein); J04488 (Ptgds, Prostaglandin D synthase); X71127 (c1qb, complement component 1-q (beta polypeptide)); J03752 (Microsomal GST-1, glutathione S-transferase); J03481 (Qdpr, Dihydropteridine reductase); L40362 (MHC class I RT1.C-type protein); M94918 (Hbb, beta hemoglobin); M55534 (Cryab, alpha crystallin polypeptide 2); U17919 (Aif1, allograft inflammatory factor 1); M15562 (MHC class II RT1.u-D-alpha chain); AA799645 (Phospholemman, FXYD domain-containing ion transport regulator 1); X13044 (Cd74, CD74 antigen); M24324 (RTS, MHC class I RT1 (RTS) (u haplotype)); U31866 (Nclone10); M32062 (Fcgr3, Fc IgG receptor III (low affinity)); AF095741 (Mg87); L03201 (Ctss, cathepsin S); M27905 (Rpl21, Ribosomal protein L21); D38380 (Tf, Transferrin); AA893493 (RPL26, Ribosomal protein L26); AJ222813 (I118, interleukin 18); E13541 (Cspg5, chondroitin sulfate proteoglycan 5); X54096 (Lcat, Lecithin-cholesterol acyltransferase); L40364 (RT1Aw2, RT1 class Ib); D28111 (MOBP, myelin-associated oligodendrocytic basic protein); M32016 (Lamp2, lysosomal-associated membrane protein 2); X13167 (NF1-A, nuclear factor 1 A); U26356 (S100A1, S100 protein (alpha chain)); AI231213 (Kangai 1, suppression of tumorigenicity 6); AI170268 (Ptgfr, Prostaglandin F receptor); X62952 (Vim, vimentin); AI014169 (Vdup1, vitamin D-upregulated); AA850219 (Anx3, Annexin A3); D84477 (Rhoa, ras-related homolog A2); X52477 (C3, Complement component 3); X52619 (Rpl28, Ribosomal protein L28); X06554 (S-MAG, myelin-associated glycoprotein C-term); Z50144 (Kat2, kynurenine aminotransferase II); X14181 (RPL18A, Ribosomal protein L18a); AA892333 (Tuba1, alpha-tubulin); U67082 (KZF-1, Kruppel associated box (KRAB) zinc finger 1); U11760 (Vcp, valosin-containing protein); AF048828 (VDAC1, voltage-dependent anion channel 1); M31076 (TNF-alpha, Transforming growth factor (alpha)); S83279 (HSDIV, 17-beta-hydroxysteroid dehydrogenase type IV); AI102103 (Pik4cb, Phosphatidylinositol 4-kinase); X56325 (Hba1, alpha 1 hemoglobin); X73371 (FCGR2, Low affinity immunoglobulin gamma Fc receptor II); X78848 (Gsta1, Glutathione-S-transferase (alpha type)); U92564 (Roaz, Olf-1/EBF associated Zn finger protein); AI171462 (Cd24, CD24 antigen); X83231 (PAIHC3, Pre-alpha-inhibitor, heavy chain 3); AF097593 (Ca4, cadherin 2-type 1 (neuronal)); X68283 (Rpl29, Ribosomal protein L29); S55427 (Pmp, peripheral myelin protein); AA818025 (Cd59, CD59 antigen); E01534 (Rps15, Ribosomal protein S15); U37138 (Sts, Steroid sulfatase); X55572 (Apod, Apolipoprotein D); AI028975 (AP-1, adaptor protein complex (beta 1)); L16995 (ADD1, adipocyte determination/differentiation-dependent factor 1); U07971 (Transamidinase, Glycine amidinotransferase, mitochondrial); L07736 (Cpt1a, Carnitine palmitoyltransferase 1 alpha (liver)); AI237535 (LitaF, LPS-induced TNF-alpha factor); AI175486 (Rps7, Ribosomal protein S7); U32498 (RSEC8, rat homolog of yeast sec8); X53504 (RPL12, Ribosomal protein L12); AF023621 (Sort1, sortilin); AF083269 (P41-Arc, actin-related protein complex 1b); AA891810 (GST, Glutathione S-transferase); M77694 (Fah, fimarylacetoacetate hydrolase); M22357 (MAG, myelin-associated glycoprotein); AI230712 (Pace4, Subtilisin-like endoprotease); AF008439 (NRAMP2, Natural resistance-associated macrophage protein 2); U77829 (Gas-5, growth arrest homolog); U92081 (Gp38, Glycoprotein 38); AA891445 (Skd3, suppressor of K⁺ transport defect 3); AI177161 (Nfe212, NF-E2-related factor 2); AF031430 (Stx7, Syntaxin 7); L35921 (Ggamma, GTP-binding protein (gamma subunit)); X62322 (Gm, Granulin); AF028784 (GFAP, glial fibrillary acidic protein); and AI234146 (Csrp1, Cysteine rich protein 1).

Using the method of the invention, we have further identified a set of genes and ESTs that changed with age (p≦0.01). These include AA891651 (rc_AA891651 EST195454 cDNA); AI070108 (rc_AI070108 UI-R-Y0-lu-a-09-0-UI.s1 cDNA); AI176689 (mitogen-activated protein kinase kinase 6); AI012051 (rc_AI012051 EST206502 cDNA); AI233365 (rc_AI233365 EST230053 cDNA); AA892532 (rc_AA892532 EST196335 cDNA); AA893185 (rc_AA893185 EST196988 cDNA); AA964320 (rc_AA964320 UI-R-C0-gu-e-09-0-UI.s1 cDNA); AA963449 (rc_AA963449 UI-R-E1-gj-e-08-0-UI.s1 cDNA); AA859632 (rc_AA859632 UI-R-E0-bs-h-08-0-UI.s1 cDNA); AI169265 (Atp6s1); AA850781 (rc_AA850781 EST193549 cDNA); AJ222813 (interleukin 18); D38380 (Transferrin); J03481 (dihydropteridine reductase); M24542 (Rieske iron-sulfur protein); L03294 (Lipoprotein lipase); L19998 (sulfotransferase family 1A, phenol-preferring, member 1); U53922 (DnaJ-like protein (RDJ1)); X54793 (liver heat shock protein (hsp60)); X62952 (vimentin); M55534 (Crystallin, alpha polypeptide 2); J03752 (microsomal glutathione S-transferase 1); X64401 (Cytochrome P450, subfamily 111A, polypeptide 3); X78848 (Gsta1); AF016387 (retinoid X receptor gamma); AF031430 (syntaxin 7); AF051561 (solute carrier family 12, member 2); AF076183 (cytosolic sorting protein PACS-1a (PACS-1)); AF095576 (adaptor protein with pleckstrin homology and src homology 2 domains); AF095741 (MG87); AF097593 (cadherin 2, type 1, N-cadherin (neuronal)); AF104362 (osteoadherin); D10699 (ubiquitin carboxy-terminal hydrolase L1); D28111 (myelin-associated oligodendrocytic basic protein); D37951 (MIBP1 (c-myc intron binding protein 1)); D84477 (RhoA); L13202 (RATHFH2 HNF-3/fork-head homolog-2 (HFH-2)); L26292 (Kruppel-like factor 4 (gut)); L46873 (solute carrier family 15 (oligopeptide transporter), member 1); M13100 (RATLIN3A long interspersed repetitive DNA sequence LINE3 (L1Rn)); M27207 (procollagen, type I, alpha 1); M92433 (Zinc-finger transcription factor NGFI-C (early response gene)); M94918 (Hemoglobin, beta); M94919 (Hemoglobin, beta); S55427 (Peripheral myelin protein); S68245 (carbonic anhydrase 4); S82649 (Narp=neuronal activity-regulated pentraxin); U10894 (allograft inflammatory factor 1); U26356 (RNSHUNA1 S100A1 gene); U75397 (RNKROX2 Krox-24); U75405 (procollagen, type I, alpha 1); U77829 (RNU77829 gas-5 growth arrest homolog non-translated sequence); U92081 (glycoprotein 38); X06554 (RNMAGSR myelin-associated glycoprotein (S-MAG) C-term); X13167 (Nuclear Factor IA); X14181 (RRRPL18A ribosomal protein L18a); X56325 (Hemoglobin, alpha 1); X60351 (Crystallin, alpha polypeptide 2); E13541 (chondroitin sulfate proteoglycan 5); M22357 (1B236/myelin-associated glycoprotein (MAG)); M24026 (RT1 class Ib gene); M24324 (MHC class I RT1 (RTS) (u haplotype)); J04488 (Prostaglandin D synthase); M15191 (Tachykinin (substance P, neurokinin A, neuropeptide K, neuropeptide gamma)); M74223 (VGF); U17254 (immediate early gene transcription factor NGFI-B); U08259 (Glutamate receptor, ionotropic, N-methyl D-aspartate 2C); U19866 (activity regulated cytoskeletal-associated protein); L40364 (RT1 class Ib gene); U17919 (allograft inflammatory factor 1); U78102 (early growth response 2); U67082 (KRAB-zinc finger protein KZF-1); U77777 (interleukin 18); D78018 (Nuclear Factor IA); U92564 (Olf-1/EBF associated Zn finger protein Roaz); AF008439 (Solute carrier family 11 member 2 (natural resistance-associated macrophage protein 2)); AB003726 (RuvB-like protein 1); M83561 (Glutamate receptor, ionotropic, kainate 1); AI639151 (mixed-tissue library cDNA clone rx02802 3); AI639247 (mixed-tissue library cDNA clone rx03939 3); AI639381 (mixed-tissue library cDNA clone rx01495 3); AI639532 (mixed-tissue library cDNA clone rx01030 3); AA799645 (FXYD domain-containing ion transport regulator 1); AA900516 (Pdi2); AI014169 (Vdup1); AI030089 (Nopp140); AI102299 (Bid3); AA818025 (CD59 antigen); AI170268 (Prostaglandin F receptor); AI171462 (CD24 antigen); AI171966 (ESTs, Highly similar to SPS2 MOUSE SELENIDE, WATER DIKINASE 2 [M. musculus]); AI76456 (ESTs, Weakly similar to ABP2_HUMAN ENDOTHELIAL ACTIN-BINDING PROTEIN [H. sapiens]); AI177161 (NF-E2-related factor 2); AI179576 (Hemoglobin, beta); AI230712 (Subtilisin-like endoprotease); AI230914 (farnesyltransferase beta subunit); AI231213 (kangai 1 (suppression of tumorigenicity 6), prostate); AI237731 (Lipoprotein lipase); M83745 (Protein convertase subtilisin/kexin, type I); M27905 (ribosomal protein L21); M32016 (Lysosomal-associated membrane protein 2); M11071 (RT1 class Ib gene); M15562 (MHC class II RT1.u-D-alpha chain); M15880 (Neuropeptide Y); L08595 (nuclear receptor subfamily 4, group A, member 2); M18416 (Early growth response 1); L40362 (MHC class I RT1.C-type protein); Z50144 (kynurenine/alpha-aminoadipate aminotransferase); X71127 (complement component 1, q subcomponent, beta polypeptide); U44948 (smooth muscle cell LIM protein (SmLIM)); AA850219 (Annexin A3); X73371 (FCGR2); X57281 (Glycine receptor alpha 2 subunit (glycine receptor, neonatal)); X83231 (pre-alpha-inhibitor); X52477 (Complement component 3); X16554 (phosphoribosyl pyrophosphate synthetase 1); X78605 ((Sprague Dawley) rab4b ras-homologous GTPase); X82445 (nuclear distribution gene C homolog (Aspergillus)); X52619 (ribosomal protein L28); X68283 (ribosomal protein L29); X13044 (CD74 antigen (invariant polpypeptide of major histocompatibility class II antigen-associated)); X54096 (Lecithin-cholesterol acyltransferase); U31866 (Nclone10); U72620 (Lot1); U66470 (rCGR11); M31018 (RT1 class Ib gene); U90887 (arginase type II); M18467 (Glutamate oxaloacetate transaminase 2, mitochondrial (aspartate aminotransferase 2)); M64780 (Agrin); U87627 (putative monocarboxylate transporter (MCT3)); AF019974 (Chromogranin B, parathyroid secretory protein); L03201 (cathepsin S); AB008538 (HB2); D89340 (dipeptidylpeptidase III); M77694 (fumarylacetoacetate hydrolase); M32062 (Fc-gamma receptor); L21192 (brain abundant, membrane attached signal protein 2); M37584 (H2afz); AA858588 (ESTs, Weakly similar to ODP2 RAT DIHYDROLIPOAMIDE ACETYLTRANSFERASE COMPONENT OF PYRUVATE DEHYDROGENASE COMPLEX [R. norvegicus]); AA858617 (rc_AA858617 UI-R-E0-bq-b-06-0-UI.s1 cDNA); AA859562 (rc_AA859562 UI-R-E0-by-b-03-0-UI.s1 cDNA); AA859626 (rc_AA859626 UI-R-E0-bs-h-02-0-UI.s1 cDNA); AA859690 (rc_AA859690 UI-R-E0-bx-e-11-0-UI.s1 cDNA); AA859777 (rc_AA859777 UI-R-E0-bu-e-10-0-UI.s1 cDNA); AA859975 (LOC64201); AA860030 (UI-R-E0-bz-e-07-0-UI.s2 cDNA); AA866291 (rc_AA866291 UI-R-A0-ac-e-12-0-UI.s3 cDNA); AA866409 (rc_AA866409 UI-R-E0-ch-a-03-0-UI.s1 cDNA); AA866411 (NDN); AA874794 (Bex3); A874887 (rc_AA874887 UI-R-E0-ci-g-10-0-UI.s1 cDNA); AA875004 (rc_AA875004 UI-R-E0-cb-b-07-0-UI.s1 cDNA); AA875037 (rc_AA875037 UI-R-E0-cb-a-03-0-UI.s1 cDNA); AA875047 (TCPZ); AA875059 (rc_AA875059 UI-R-E0-cb-f-04-0-UI.s1 cDNA); AA875129 (rc_AA875129 UI-R-E0-bu-e-01-0-UI.s2 cDNA); H31418 (rc_H31418 EST105434 cDNA); H31665 (rc_H31665 EST105952 cDNA); H32977 (rc_H32977 EST108553 cDNA); H33725 (associated molecule with the SH3 domain of STAM); AA891037 (rc_AA891037 EST194840 cDNA); AA891445 (Skd3); AA891690 (ESTs, Weakly similar to SERC_HUMAN PHOSPHOSERINE AMINOTRANSFERASE [H. sapiens]); AA891717 (USF1); AA891734 (rc_AA891734 EST195537 cDNA); AA891785 (rc_AA891785 EST195588 cDNA); AA891810 (ESTs, Highly similar to GTK1 RAT GLUTATHIONE S-TRANSFERASE, MITOCHONDRIAL [R. norvegicus]); AA891965 (rc_AA891965 EST195768 cDNA); AA892333 (Tuba1); AA892353 (ESTs, Moderately similar to JC5823 NADH dehydrogenase [H. sapiens]); AA892511 (rc_AA892511 EST196314 cDNA); AA892986 (rc_AA892986 EST196789 cDNA); AA893032 (ESTs, Moderately similar to CALX RAT CALNEXIN PRECURSOR [R. norvegicus]); AA893082 (rc_AA893082 EST196885 cDNA); AA893493 (RPL26); AA893607 (rc_AA893607 EST197410 cDNA); AA893708 (KIAA0560); AA893743 (rc_AA893743 EST197546 cDNA); AA894104 (rc_AA894104 EST197907 cDNA); AA799449 (EST, Weakly similar to UBP4 MOUSE UBIQUITIN CARBOXYL-TERMINAL HYDROLASE 4 [M. musculus]); AA799779 (acyl-CoA:dihydroxyacetonephosphate acyltransferase); AA799803 (ESTs, Weakly similar to K1CU RAT KERATIN, TYPE I CYTOSKELETAL 21 [R. norvegicus]); AA799854 (rc_AA799854 EST189351 cDNA); AA799996 (rc_AA799996 EST189493 cDNA); AA800693 (rc_AA800693 EST190190 cDNA); AA800708 (ESTs, Weakly similar to S28312 hypothetical protein F02A9.4-Caenorhabditis elegans [C. elegans]); AA800794 (HT2A); and AA800948 (Tuba4).

We have also identified age-related ESTs, including AA963449 (UI-R-E1-gj-e-08-0-UI.s1 cDNA); AA892532 (EST196335 cDNA); AA859626 (UI-R-E0-bs-h-02-0-UI.s1 cDNA); AA893743 (EST197546 cDNA); AI233365 (EST230053 cDNA); H31665 (EST105952 cDNA); AA892353 (ESTs, Moderately similar to JC5823 NADH dehydrogenase); AI639247 (mixed-tissue library cDNA clone rx03939 3); AA858617 (UI-R-E0-bq-b-06-0-UI.s1 cDNA); AI639429 (mixed-tissue library cDNA clone rx00973 3); AA858620 (UI-R-E0-bq-b-09-0-UI.s1 cDNA); AA866291 (UI-R-A0-ac-e-12-0-UI.s3 cDNA); AA894104 (EST197907 cDNA); AA799996 (EST189493 cDNA); AA892805 (EST196608 cDNA); AI639019 (mixed-tissue library cDNA clone rx01107 3); AA799538 (EST189035 cDNA); AI070108 (UI-R-Y0-lu-a-09-0-UI.s1 cDNA); AA866409 (UI-R-E0-ch-a-03-0-UI.s1 cDNA); AA859632 (UI-R-E0-bs-h-08-0-UI.s1 cDNA); AA891651 (EST195454 cDNA); AA893032 (ESTs, Moderately similar to CALX calnexin precursor); AA891965 (EST195768 cDNA); AA800708 (ESTs, Weakly similar to S28312 hypothetical protein F02A9.4); AA964320 (UI-R-C0-gu-e-09-0-UI.s1 cDNA); AA893173 (EST196976 cDNA); H32977 (EST108553 cDNA); AA874887 (UI-R-E0-ci-g-10-0-UI.s1 cDNA); AA850781 (EST193549 cDNA); AI176456 (ESTs, Weakly similar to endothelial actin-binding protein); H31418 (EST105434 cDNA); AA858588 (ESTs, Weakly similar to ODP2 dihydrolipoamide acetyl transferase); AA891785 (EST195588 cDNA); AA799803 (ESTs, Weakly similar to K1CU cytoskeletal keratin (type 1)); AA799449 (EST, Weakly similar to UBP4 ubiquitin carboxyl-terminal hydrolase 4); AA859777 (UL-R-E0-bu-e-10-0-UI.s1 cDNA); AI639532 (mixed-tissue library cDNA clone rx01030 3); AA875059 (UI-R-E0-cb-f-04-0-UI.s1 cDNA); AI012051 (EST206502 cDNA); AA800549 (EST190046 cDNA); AA799854 (EST189351 cDNA); and AA892520 (EST196323 cDNA).

Those of skill in the genomics art will understand that the identified genes and ESTs have utility as biomarkers of brain aging. Those of skill in the genomics art will understand that the mammalian homologues (including rat, mouse and human homologues) the identified genes and ESTs are also as biomarkers of brain aging. The easiest method for identifying mammalian homologues of the identified genes and ESTs is by identifying the homologues in the GenBank database, preferably, or in the SwissProtein and the Genome Ontology databases. Additional guidance as to homology can be obtained by using commercially available computer programs, such as DNA Strider and Wisconsin GCG, and following the instructions for the determination of the degree of homolgy between selected polynucleotides.

The foregoing description has been presented only for the purposes of illustration and is not intended to limit the invention to the precise form disclosed, but by the claims appended hereto. 

1. A method for identifying a biomarker for brain aging, wherein the biomarker is a polynucleotide or a polypeptide encoded by said polynucleotide, comprising the steps of: (a) obtaining a set of polynucleotides obtained from a set of brain samples, wherein the members of the set of brain samples were obtained from members of a set of mammals, wherein the set of mammals contains more than two members and wherein the set of mammals comprises young, mid-aged and aged members; (b) identifying the identity and amount of the members of the set of polynucleotides present in the brain samples; (c) deleting from the set of polynucleotides; (1) quality control oligonucleotides; (2) polynucleotides in which the difference between the young and the aged members did not comprise at least 75% of the maximum normalized difference among the members; and (d) testing by a conventional statistical test for a significant effect of aging across the young, mid-aged and aged members; wherein the polynucleotides, and polypeptide encoded by said polynucleotides, that are both significantly altered in an age-dependent fashion across age are identified as biomarkers for brain aging.
 2. The identification method of claim 1, further comprising the step of: (e) correlating the identity and amount of the members of the set of polynucleotides present in the brain samples with cognitive performance in a behavioral test, using a conventional statistical correlation test; wherein the polynucleotides, and polypeptide encoded by said polynucleotides, that are both significantly altered in an age-dependent fashion as well as significantly correlated with cognitive performance across age are identified as biomarkers for brain aging.
 3. The identification method of claim 1, wherein the biomarker for brain aging is a biomarker for an age-related neurodegenerative condition.
 4. The identification method of claim 3, wherein the age-related neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 5. The identification method of claim 1, wherein the brain sample is a hippocampal sample.
 6. The identification method of claim 1, wherein the mammal is selected from the group consisting of rat, mouse and human.
 7. The identification method of claim 1, wherein the biomarker for brain aging is an expressed sequence tag (EST).
 8. The identification method of claim 1, further comprising, in the deletion step (c), the step of: (3) deleting, from the set of polynucleotides, polynucleotides for expressed sequence tags (ESTs) which have not been associated with known genes.
 9. The identification method of claim 1, further comprising, in the deletion step (c), the step of: (3) deleting, from the set of polynucleotides, polynucleotides that are not expressed sequence tags (ESTs).
 10. The identification method of claim 1, wherein the conventional statistical test in step (d) is ANOVA or student's t test.
 11. The identification method of claim 1, wherein the testing in step (d) is testing by 1-way ANOVA for a significant effect of aging p<0.05.
 12. The identification method of claim 1, wherein the behavioral tests of step (e) specifically test for cognitive deficits related to the region of the brain from which the brain sample has been obtained in step (a).
 13. The identification method of claim 1, wherein the identification of the identity and amount of the members of the set of polynucleotides present in the brain samples in step (b) is by microarray analysis.
 14. The identification method of claim 1, wherein the significant effect in step (d) is p<0.025.
 15. The identification method of claim 1, wherein the significant effect in step (d) is p<0.01.
 16. The identification method of claim 1, wherein the significant effect in step (d) is p<0.001.
 17. The identification method of claim 1, wherein the behavioral test in step (e) is selected from the group consisting of the Morris spatial water maze (SWM) and the object memory task (OMT).
 18. The identification method of claim 1, wherein the behavioral tests in step (e) are selected from the group consisting of tests for Alzheimer's disease and tests for Parkinson's disease.
 19. The identification method of claim 1, wherein the correlation of the identity and amount of the members of the set of polynucleotides present in the brain samples with cognitive performance in behavioral tests is a Pearson or Spearman correlation of expression with behavior.
 20. The identification method of claim 19, wherein the correlation is p<0.025.
 21. The identification method of claim 19, wherein the correlation is p<0.01.
 22. The identification method of claim 19, wherein the correlation is p<0.001.
 23. A set of biomarkers for brain aging, comprising mammalian polynucleotides and polypeptides encoded by said polynucleotides: (a) wherein the set of biomarkers comprises at least two members; (b) wherein the brain expression patterns of the members of the set are significantly altered with aging as determined by a conventional statistical test, with p<0.05; (c) wherein the brain expression patterns of the members of the set are correlated across age groups with cognitive performance in behavioral tests, using a conventional statistical correlation test with a correlation of p<0.05 between brain expression and cognitive performance; and (d) wherein the cognitive performance in behavioral tests significantly altered with aging as determined by a conventional statistical test.
 24. The set of biomarkers of claim 23, wherein the biomarkers further correlate with a behavioral measure of functional impairment.
 25. The set of biomarkers of claim 23, wherein the behavioral measure of functional impairment is a test for an age-related neurodegenerative condition.
 26. The set of biomarkers of claim 25, wherein the age-related neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 27. The set of biomarkers of claim 23, wherein the mammal is selected from the group consisting of rat, mouse and human.
 28. The set of biomarkers of claim 23, wherein the conventional statistical method in step (b) is ANOVA or student's t-test.
 29. The set of biomarkers of claim 23, wherein the correlation in step (c) is tested by a correlation test selected from the group consisting of Pearson's correlation test and Spearman's correlation test.
 30. The set of biomarkers of claim 23, wherein the age groups in step (c) comprises young, mid-aged and aged.
 31. The set of biomarkers of claim 23, wherein the conventional statistical test in step (d) is ANOVA or student's t-test.
 32. The set of biomarkers of claim 23, wherein at least one member of the set of biomarkers is a polynucleotide, or a polypeptide encoded by said polynucleotide, selected from the group consisting of L03294 (Lpl, lipoprotein lipase) (SEQ ID NO:37); M18416 (Egr1, Early growth response 1 (Krox-24)) (SEQ ID NO:8); S68245 (Ca4, carbonic anhydrase 4) (SEQ ID NO:38); M64780 (Agm, Agrin) (SEQ ID NO:1); M27207 (Col1a1, Procollagen-type I (alpha 1)) (SEQ ID NO:32); X16554 (Prps1, Phosphoribosyl pyrophosphate synthetase 1) (SEQ ID NO:51); M92433 (NGFI-C, Zinc-finger transcription factor (early response gene)) (SEQ ID NO:9); AA859975 (LOC64201, 2-oxoglutarate carrier) (SEQ ID NO:39); L08595 (Nuclear receptor subfamily 4, group A, member 2) (SEQ ID NO:10); M24542 (RISP, Rieske iron-sulfur protein) (SEQ ID NO:40); AI030089 (Nopp130, nucleolar phosphoprotein p130) (SEQ ID NO:11); AF104362 (Omd, Osteomodulin (osteoadherin)) (SEQ ID NO:33); L46873 (Slc15a1, Oligopeptide transporter) (SEQ ID NO:47; AI176689 (MAPKK 6, mitogen-activated protein kinase kinase 6) (SEQ ID NO:19); U66470 (rCGR11, Cell growth regulator) (SEQ ID NO:52); AF016387 (RXRG, retinoid X-receptor gamma) (SEQ ID NO:12); M18467 (Got2, glutamate oxaloacetate transaminase 2) (SEQ ID NO:41); X54793 (Hsp60, heat shock protein 60) (SEQ ID NO:62); X64401 (Cyp3a3, Cytochrome P450-subfamily IIIA (polypeptide 3)) (SEQ ID NO:42); M37584 (H2afz, H2A histone family (member Z)) (SEQ ID NO:53); L21192 (GAP-43, membrane attached signal protein 2 (brain)) (SEQ ID NO:2); AA875047 (TCPZ, T-complex protein 1 (zeta subunit)) (SEQ ID NO:63); U90610 (Cxcr4, CXC chemokine receptor) (SEQ ID NO:54); AF003904 (CRH-binding protein) (SEQ ID NO:27); U83880 (GPDH-M, glycerol-3-phosphate dehydrogenase, mitochondrial) (SEQ ID NO:43); X89703 (TPCR19, Testis Polymerase Chain Reaction product 19) (SEQ ID NO:20); D63886 (MMP16, matrix metalloproteinase 16) (SEQ ID NO:34); J05499 (GLS, glutaminase (mitochondrial)) (SEQ ID NO:44); D21799 (Psmb2, Proteasome subunit (beta type 2)) (SEQ ID NO:64); AA800794 (HT2A, zinc-finger protein) (SEQ ID NO:13); U90887 (Arg2, arginase type II) (SEQ ID NO:45); S82649 (Narp, neuronal activity-regulated pentraxin) (SEQ ID NO:3); M74223 (VGF, neurosecretory protein) (SEQ ID NO:4); AA874794 (Bex3, brain expressed X-linked 3) (SEQ ID NO:55); M15191 (Tac1, Tachykinin) (SEQ ID NO:28); AA892506 (coronin, actin binding protein 1A) (SEQ ID NO:56); L04485 (MAPPK1, mitogen-activated protein kinase kinase 1) (SEQ ID NO:21); AA799641 (S 164, Contains a PWI domain associated with RNA splicing) (SEQ ID NO:14); AA817892 (Gnb2, Guanine nucleotide binding protein (beta 2 subunit)) (SEQ ID NO:22); AA893939 (DSS1, deleted in split hand/split foot protein 1) (SEQ ID NO:57); AF000901 (P58/P45, Nucleoporin p58) (SEQ ID NO:23); AF087037 (Btg3, B-cell translocation gene 3) (SEQ ID NO:58); AB000280 (PHT1, peptide/histidine transporter) (SEQ ID NO:48); M87854 (Beta-ARK-1, beta adrenergic receptor kinase 1) (SEQ ID NO:24); U06099 (Prdx2, Peroxiredoxin 2) (SEQ ID NO:59); AF058795 (Gb2, GABA-B receptor) (SEQ ID NO:25; AA800517 (VAP1, vesicle associated protein) (SEQ ID NO:26); U63740 (Fez1, Protein kinase C-binding protein Zeta1) (SEQ ID NO:5); U53922 (Hsj2, DnaJ-like protein (RDJ1)) (SEQ ID NO:65); U78102 (Egr2, Early growth response 2) (SEQ ID NO 5); U44948 (SmLIM, smooth muscle cell LIM protein) (SEQ ID NO:16); U87627 (MCT3, putative monocarboxylate transporter) (SEQ ID NO:49); AB020504 (PMF31, highly homologus to mouse F-box-WD40 repeat protein 6) (SEQ ID NO:67); M21354 (Col3a1, collagen type III alpha-1) (SEQ ID NO:35); AA893664 (Temo, sertoli cell marker (KIAA0077 protein fragment)) (SEQ ID NO:68); AB010437 (CDH8, Cadherin-8) (SEQ ID NO:36); M22756 (Ndufv2, mitochondrial NADH dehydrogenase (24 kDa)) (SEQ ID NO:46); AA799389 (Rab3B, ras-related protein) (SEQ ID NO:50); AI172476 (Tieg-1, TGF-beta-inducible early growth response protein 1) (SEQ ID NO:60); AF091563 (Olfactory receptor) (SEQ ID NO:29); M64376 (Olfactory protein) (SEQ ID NO:30); J04488 (Ptgds, Prostaglandin D synthase) (SEQ ID NO:69); X71127 (c1qb, complement component 1-q (beta polypeptide)) (SEQ ID NO:70); J03752 (Microsomal GST-1, glutathione S-transferase) (SEQ ID NO:71); J03481 (Qdpr, Dihydropteridine reductase) (SEQ ID NO:115); L40362 (MHC class I RT1.C-type protein) (SEQ ID NO:72); M94918 (Hbb, beta hemoglobin) (SEQ ID NO:125); M55534 (Cryab, alpha crystallin polypeptide 2) (SEQ ID NO:105); U17919 (Aif1, allograft inflammatory factor 1) (SEQ ID NO:73); M15562 (MHC class II RT1.u-D-alpha chain) (SEQ ID NO:74); AA799645 (Phospholemman, FXYD domain-containing ion transport regulator 1) (SEQ ID NO:130); X13044 (Cd74, CD74 antigen) (SEQ ID NO:75); M24324 (RTS, MHC class I RT1 (RTS) (u haplotype)) (SEQ ID NO:76); U31866 (Nclone10) (SEQ ID NO:126); M32062 (Fcgr3, Fc IgG receptor III (low affinity)) (SEQ ID NO:77); AF095741 (Mg87) (SEQ ID NO:151); L03201 (Ctss, cathepsin S) (SEQ ID NO:131); M27905 (Rpl21, Ribosomal proteinL21) (SEQ ID NO:132); D38380 (Tf, Transferrin) (SEQ ID NO:127); AA893493 (RPL26, Ribosomal protein L26) (SEQ ID NO:133); AJ222813 (118, interleukin 18) (SEQ ID NO:78); E13541 (Cspg5, chondroitin sulfate proteoglycan 5) (SEQ ID NO:102); X54096 (Lcat, Lecithin-cholesterol acyltransferase) (SEQ ID NO:110); L40364 (RT1Aw2, RT1 class Ib) (SEQ ID NO:79); D28111 (MOBP, myelin-associated oligodendrocytic basic protein) (SEQ ID NO:106); M32016 (Lamp2, lysosomal-associated membrane protein 2) (SEQ ID NO:142); X13167 (NF1-A, nuclear factor 1 A) (SEQ ID NO:89); U26356 (S100A1, S100 protein (alpha chain)) (SEQ ID NO:95); AI231213 (Kangai 1, suppression of tumorigenicity 6) (SEQ ID NO:80); AI170268 (Ptgfr, Prostaglandin F receptor) (SEQ ID NO:81); X62952 (Vim, vimentin) (SEQ ID NO:119); AI014169 (Vdup1, vitamin D-upregulated) (SEQ ID NO:152); AA850219 (Anx3, Annexin A3) (SEQ ID NO:96); D84477 (Rhoa, ras-related homolog A2) (SEQ ID NO:97); X52477 (C3, Complement component 3) (SEQ ID NO:82); X52619 (Rpl28, Ribosomal protein L28) (SEQ ID NO:134); X06554 (S-MAG, myelin-associated glycoprotein C-term) (SEQ ID NO:107); Z50144 (Kat2, kynurenine aminotransferase II) (SEQ ID NO:116); X14181 (RPL18A, Ribosomal protein L18a) (SEQ ID NO:135); AA892333 (Tuba1, alpha-tubulin) (SEQ ID NO:120); U67082 (KZF-1, Kruppel associated box (KRAB) zinc finger 1) (SEQ ID NO:90); U11760 (Vcp, valosin-containing protein) (SEQ ID NO:121); AF048828 (VDAC1, voltage-dependent anion channel 1) (SEQ ID NO:98); M31076 (TNF-alpha, Transforming growth factor (alpha)) (SEQ ID NO:136); S83279 (HSDIV, 17-beta-hydroxysteroid dehydrogenase type IV) (SEQ ID NO:111); AI102103 (Pik4cb, Phosphatidylinositol 4-kinase) (SEQ ID NO:99); X56325 (Hba1, alpha 1 hemoglobin) (SEQ ID NO:128); X73371 (FCGR2, Low affinity immunoglobulin gamma Fc receptor II) (SEQ ID NO:83); X78848 (Gsta1, Glutathione-S-transferase (alpha type)) (SEQ ID NO:84); U92564 (Roaz, Olf-1/EBF associated Zn finger protein) (SEQ ID NO:91); AI171462 (Cd24, CD24 antigen) (SEQ ID NO:137); X83231 (PAIHC3, Pre-alpha-inhibitor, heavy chain 3) (SEQ ID NO:103); AF097593 (Ca4, cadherin 2-type 1 (neuronal)) (SEQ ID NO:104); X68283 (Rpl29, Ribosomal protein L29) (SEQ ID NO:138); S55427 (Pmp, peripheral myelin protein) (SEQ ID NO:108); AA818025 (Cd59, CD59 antigen) (SEQ ID NO:85); E01534 (Rps15, Ribosomal protein S15) (SEQ ID NO:143); U37138 (Sts, Steroid sulfatase) (SEQ ID NO:112); X55572 (Apod, Apolipoprotein D) (SEQ ID NO:113); AI028975 (AP-1, adaptor protein complex (beta 1)) (SEQ ID NO:144); L16995 (ADD1, adipocyte determination/differentiation-dependent factor 1) (SEQ ID NO:92); U07971 (Transamidinase, Glycine amidinotransferase, mitochondrial) (SEQ ID NO:117); L07736 (Cpt1a, Carnitine palmitoyltransferase 1 alpha (liver)) (SEQ ID NO:114); AI237535 (LitaF, LPS-induced TNF-alpha factor) (SEQ ID NO:93); AI175486 (Rps7, Ribosomal protein S7) (SEQ ID NO:145); U32498 (RSEC8, rat homolog of yeast sec8) (SEQ ID NO:122); X53504 (RPL12, Ribosomal protein L12) (SEQ ID NO:139); AF023621 (Sort1, sortilin) (SEQ ID NO:146); AF083269 (P41-Arc, actin-related protein complex 1b) (SEQ ID NO:123); AA891810 (GST, Glutathione S-transferase) (SEQ ID NO:86); M77694 (Fah, fumarylacetoacetate hydrolase) (SEQ ID NO:118); M22357 (MAG, myelin-associated glycoprotein) (SEQ ID NO:109); AI230712 (Pace4, Subtilisin-like endoprotease) (SEQ ID NO:147); AF008439 (NRAMP2, Natural resistance-associated macrophage protein 2) (SEQ ID NO:129); U77829 (Gas-5, growth arrest homolog) (SEQ ID NO:140); U92081 (Gp38, Glycoprotein 38) (SEQ ID NO:87); AA891445 (Skd3, suppressor of K⁺ transport defect 3) (SEQ ID NO:148); AI177161 (Nfe212, NF-E2-related factor 2) (SEQ ID NO:94); AF031430 (Stx7, Syntaxin 7) (SEQ ID NO:149); L35921 (Ggamma, GTP-binding protein (gamma subunit)) (SEQ ID NO:100); X62322 (Gm, Granulin) (SEQ ID NO:88); AF028784 (GFAP, glial fibrillary acidic protein) (SEQ ID NO:124); AI234146 (Csrp1, Cysteine rich protein 1) (SEQ ID NO:141) and mammalian homologues thereof.
 33. The set of biomarkers of claim 23, wherein at least one member of the set of biomarkers is an expressed sequence tag (EST).
 34. The set of biomarkers of claim 23, for use in the measurement of age-dependent cognitive decline.
 35. The set of biomarkers of claim 34, wherein the age-dependent cognitive decline is an age-related neurodegenerative condition.
 36. The set of biomarkers of claim 35, wherein the age-related neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 37. The set of biomarkers of claim 23, for use in the measurement of degree of the safety or effectiveness of compounds or procedures directed against age-related cognitive decline.
 38. A set of biomarkers for brain aging, comprising mammalian polynucleotides and polypeptides encoded by said polypeptides: (a) wherein the set of biomarkers comprises at least two members; (b) wherein the brain expression patterns of the members of the set are significantly altered with aging as measured by a conventional statistical method at a significance level of p<0.01.
 39. The set of biomarkers of claim 38, wherein the mammal is selected from the group consisting of rat, mouse and human.
 40. The set of biomarkers of claim 38, wherein the conventional statistical method is ANOVA or student's t-test.
 41. The set of biomarkers of claim 38, wherein at least one member of the set of biomarkers is a polynucleotide, or a polypeptide encoded by said polynucleotide, selected from the group consisting of AA891651 (rc_AA891651 EST195454 cDNA) (SEQ ID NO:173); AI070108 (rc_AI070108 UI-R-Y0-lu-a-09-0-UI.s1 cDNA) (SEQ ID NO:170); AI176689 (mitogen-activated protein kinase kinase 6) (SEQ ID NO:19); AI012051 (rc_AI012051 EST206502 cDNA) (SEQ ID NO:191); AI233365 (rc_AI233365 EST230053 cDNA) (SEQ ID NO:157); AA892532 (rc_AA892532 EST196335 cDNA) (SEQ ID NO:154); AA893185 (rc_AA893185 EST196988 cDNA) (SEQ ID NO:399); AA964320 (rc_AA964320 UI-R-C0-gu-e-09-0-UI.s1 cDNA) (SEQ ID NO:177); AA963449 (rc_AA963449 UI-R-E1-gj-e-08-0-UI.s1 cDNA) (SEQ ID NO:153); AA859632 (rc_AA859632 UI-R-E0-bs-h-08-0-UI.s1 cDNA) (SEQ ID NO:172); AI169265 (Atp6s1) (SEQ ID NO:219); AA850781 (rc_AA850781 EST193549 cDNA) (SEQ ID NO:181); AJ222813 (interleukin 18) (SEQ ID NO:78); D38380 (Transferrin) (SEQ ID NO:127); J03481 (dihydropteridine reductase) (SEQ ID NO:115); M24542 (Rieske iron-sulfur protein) (SEQ ID NO:40); L03294 (Lipoprotein lipase) (SEQ ID NO:37); L19998 (sulfotransferase family 1A, phenol-preferring, member 1) (SEQ ID NO:321); U53922 (DnaJ-like protein (RDJ1)) (SEQ ID NO:65); X54793 (liver heat shock protein (hsp60)) (SEQ ID NO:62); X62952 (vimentin) (SEQ ID NO:119); M55534 (Crystallin, alpha polypeptide 2) (SEQ ID NO:105); J03752 (microsomal glutathione S-transferase 1) (SEQ ID NO:71); X64401 (Cytochrome P450, subfamily 111A, polypeptide 3) (SEQ ID NO:42); X78848 (Gsta1) (SEQ ID NO:84); AF016387 (retinoid X receptor gamma) (SEQ ID NO:12); AF031430 (syntaxin 7) (SEQ ID NO:149); AF051561 (solute carrier family 12, member 2) (SEQ ID NO:322); AF076183 (cytosolic sorting protein PACS-1a (PACS-1)) (SEQ ID NO:231); AF095576 (adaptor protein with pleckstrin homology and src homology 2 domains) (SEQ ID NO:18); AF095741 (MG87) (SEQ ID NO:151); AF097593 (cadherin 2, type 1, N-cadherin (neuronal)) (SEQ ID NO:104); AF104362 (osteoadherin) (SEQ ID NO:33); D10699 (ubiquitin carboxy-terminal hydrolase L1) (SEQ ID NO:234); D28111 (myelin-associated oligodendrocytic basic protein) (SEQ ID NO:106); D37951 (MIBP1 (c-myc intron binding protein 1)) (SEQ ID NO:230); D84477 (RhoA) (SEQ ID NO:97); L13202 (RATHFH2 HNF-3/fork-head homolog-2 (HFH-2)) (SEQ ID NO:220); L26292 (Kruppel-like factor 4 (gut)) (SEQ ID NO:218); L46873 (solute carrier family 15 (oligopeptide transporter), member 1) (SEQ ID NO:47); M13100 (RATLIN3A long interspersed repetitive DNA sequence LINE3 (L1Rn)) (SEQ ID NO:435); M27207 (procollagen, type I, alpha 1) (SEQ ID NO:32); M92433 (Zinc-finger transcription factor NGFI-C (early response gene)) (SEQ ID NO:9); M94918 (Hemoglobin, beta) (SEQ ID NO:125); M94919 (Hemoglobin, beta) (SEQ ID NO:452); S55427 (Peripheral myelin protein) (SEQ ID NO:108); S68245 (carbonic anhydrase 4) (SEQ ID NO:38); S82649 (Narp=neuronal activity-regulated pentraxin); U10894 (allograft inflammatory factor 1) (SEQ ID NO:453); U26356 (RNSHUNA1 S100A1 gene) (SEQ ID NO:95); U75397 (RNKROX2 Krox-24) (SEQ ID NO:454); U75405 (procollagen, type I, alpha 1) (SEQ ID NO:217); U77829 (RNU77829 gas-5 growth arrest homolog non-translated sequence) (SEQ ID NO:140); U92081 (glycoprotein 38) (SEQ ID NO:87); X06554 (RNMAGSR myelin-associated glycoprotein (S-MAG) C-term) (SEQ ID NO:107); X13167 (Nuclear Factor IA) (SEQ ID NO:89); X14181 (RRRPL18A ribosomal protein L18a) (SEQ ID NO:135); X56325 (Hemoglobin, alpha 1) (SEQ ID NO:128); X60351 (Crystallin, alpha polypeptide 2) (SEQ ID NO:455); E13541 (chondroitin sulfate proteoglycan 5) (SEQ ID NO:102); M22357 (1B236/myelin-associated glycoprotein (MAG)) (SEQ ID NO:109); M24026 (RT1 class Ib gene) (SEQ ID NO:456); M24324 (MHC class I RT1 (RTS) (u haplotype)) (SEQ ID NO:76); J04488 (Prostaglandin D synthase) (SEQ ID NO:69); M15191 (Tachykinin (substance P, neurokinin A, neuropeptide K, neuropeptide gamma)) (SEQ ID NO:28); M74223 (VGF) (SEQ ID NO:4); U17254 (immediate early gene transcription factor NGFI-B) (SEQ ID NOS:225 & 257); U08259 (Glutamate receptor, ionotropic, N-methyl D-aspartate 2C) (SEQ ID NO:323); U19866 (activity regulated cytoskeletal-associated protein) (SEQ ID NO:7); L40364 (RT1 class Ib gene) (SEQ ID NO:79); U17919 (allograft inflammatory factor 1) (SEQ ID NO:73); U78102 (early growth response 2) (SEQ ID NO:15); U67082 (KRAB-zinc finger protein KZF-1) (SEQ ID NO:90); U77777 (interleukin 18) (SEQ ID NO:319); D78018 (Nuclear Factor IA) (SEQ ID NO:457); U92564 (Olf-1/EBF associated Zn finger protein Roaz) (SEQ ID NO:91); AF008439 (Solute carrier family 11 member 2 (natural resistance-associated macrophage protein 2)) (SEQ ID NO:129); AB003726 (RuvB-like protein 1) (SEQ ID NO:6); M83561 (Glutamate receptor, ionotropic, kainate 1) (SEQ ID NO:101); AI639151 (mixed-tissue library cDNA clone rx02802 3) (SEQ ID NO:438); AI639247 (mixed-tissue library cDNA clone rx03939 3) (SEQ ID NO:160); AI639381 (mixed-tissue library cDNA clone rx01495 3) (SEQ ID NO:196); AI639532 (mixed-tissue library cDNA clone rx01030 3) (SEQ ID NO:189); AA799645 (FXYD domain-containing ion transport regulator 1) (SEQ ID NO:130); AA900516 (Pdi2) (SEQ ID NO:150); AI014169 (Vdup1) (SEQ ID NO:152); AI030089 (Nopp140) (SEQ ID NO:1); AI102299 (Bid3) (SEQ ID NO:320); AA818025 (CD59 antigen) (SEQ ID NO:85); AI170268 (Prostaglandin F receptor) (SEQ ID NO:81); AI171462 (CD24 antigen) (SEQ ID NO:137); AI171966 (ESTs, Highly similar to SPS2 MOUSE SELENIDE, WATER DIKINASE 2 [M. musculus]) (SEQ ID NO:437); AI176456 (ESTs, Weakly similar to ABP2_HUMAN ENDOTHELIAL ACTIN-BINDING PROTEIN [H. sapiens]) (SEQ ID NO:182); AI177161 (NF-E2-related factor 2) (SEQ ID NO:94); AI179576 (Hemoglobin, beta) (SEQ ID NO:458); AI230712 (Subtilisin-like endoprotease) (SEQ ID NO:147); AI230914 (farnesyltransferase beta subunit) (SEQ ID NO:229); AI231213 (kangai 1 (suppression of tumorigenicity 6), prostate) (SEQ ID NO:80); AI237731 (Lipoprotein lipase) (SEQ ID NO:459); M83745 (Protein convertase subtilisin/kexin, type I) (SEQ ID NO:226); M27905 (ribosomal protein L21) (SEQ ID NO:132); M32016 (Lysosomal-associated membrane protein 2) (SEQ ID NO:142); M11071 (RT1 class Ib gene) (SEQ ID NO:460); M15562 (MHC class II RT1.u-D-alpha chain) (SEQ ID NO:74); M15880 (Neuropeptide Y) (SEQ ID NO:31); L08595 (nuclear receptor subfamily 4, group A, member 2) (SEQ ID NO:10); M18416 (Early growth response 1) (SEQ ID NO:8); L40362 (MHC class I RT1.C-type protein) (SEQ ID NO:72); Z50144 (kynurenine/alpha-aminoadipate aminotransferase) (SEQ ID NO:116); X71127 (complement component 1, q subcomponent, beta polypeptide) (SEQ ID NO:70); U44948 (smooth muscle cell LIM protein (SmLIM)) (SEQ ID NO:16); AA850219 (Annexin A3) (SEQ ID NO:96); X73371 (FCGR2) (SEQ ID NO:83); X57281 (Glycine receptor alpha 2 subunit (glycine receptor, neonatal)) (SEQ ID NO:235); X83231 (pre-alpha-inhibitor) (SEQ ID NO:103); X52477 (Complement component 3) (SEQ ID NO:82); X16554 (phosphoribosyl pyrophosphate synthetase 1) (SEQ ID NO:51); X78605 ((Sprague Dawley) rab4b ras-homologous GTPase) (SEQ ID NO:66); X82445 (nuclear distribution gene C homolog (Aspergillus)) (SEQ ID NO:232); X52619 (ribosomal protein L28) (SEQ ID NO:134); X68283 (ribosomal protein L29) (SEQ ID NO:138); X13044 (CD74 antigen (invariant polpypeptide of major histocompatibility class II antigen-associated)) (SEQ ID NO:75); X54096 (Lecithin-cholesterol acyltransferase) (SEQ ID NO:110); U31866 (Nclone10) (SEQ ID NO:126); U72620 (Lot1) (SEQ ID NO:224); U66470 (rCGR11) (SEQ ID NO:52); M31018 (RT1 class Ib gene) (SEQ ID NO:461); U90887 (arginase type II) (SEQ ID NO:45); M18467 (Glutamate oxaloacetate transaminase 2, mitochondrial (aspartate aminotransferase 2)) (SEQ ID NO:41); M64780 (Agrin) (SEQ ID NO:1); U87627 (putative monocarboxylate transporter (MCT3)) (SEQ ID NO:49); AF019974 (Chromogranin B, parathyroid secretory protein) (SEQ ID NO:223); L03201 (cathepsin S) (SEQ ID NO:131); AB008538 (HB2) (SEQ ID NO:324); D89340 (dipeptidylpeptidase III) (SEQ ID NO:222); M77694 (fumarylacetoacetate hydrolase) (SEQ ID NO:118); M32062 (Fc-gamma receptor) (SEQ ID NO:77); L21192 (brain abundant, membrane attached signal protein 2) (SEQ ID NO:2); M37584 (H2afz) (SEQ ID NO:53); AA858588 (ESTs, Weakly similar to ODP2 RAT DIHYDROLIPOAMIDE ACETYLTRANSFERASE COMPONENT OF PYRUVATE DEHYDROGENASE COMPLEX [R. norvegicus]) (SEQ ID NO:184); AA858617 (rc_AA858617 UI-R-E0-bq-b-06-0-UI.s1 cDNA) (SEQ ID NO:161); AA859562 (rc_AA859562 UI-R-E0-by-b-03-0-UI.s1 cDNA) (SEQ ID NO:403); AA859626 (rc_AA859626 UI-R-E0-bs-h-02-0-UI.s1 cDNA) (SEQ ID NO:155); AA859690 (rc_AA859690 UI-R-E0-bx-e-11-0-UI.s1 cDNA) (SEQ ID NO:396); AA859777 (rc_AA859777 UI-R-E0-bu-e-10-0-UI.s1 cDNA) (SEQ ID NO:188); AA859975 (LOC64201) (SEQ ID NO:39); AA860030 (UI-R-E0-bz-e-07-0-UI.s2 cDNA) (SEQ ID NO:404); AA866291 (rc_AA866291 UI-R-A0-ac-e-12-0-UI.s3 cDNA) (SEQ ID NO:164); AA866409 (rc_AA866409 UI-R-E0-ch-a-03-0-UI.s1 cDNA) (SEQ ID NO:171); AA866411 (NDN) (SEQ ID NO:61); AA874794 (Bex3) (SEQ ID NO:55); AA874887 (rc_AA874887 UI-R-E0-ci-g-10-0-UI.s1 cDNA) (SEQ ID NO:180); AA875004 (rc_AA875004 UI-R-E0-cb-b-07-0-UI.s1 cDNA) (SEQ ID NO:397); AA875037 (rc_AA875037 UI-R-E0-cb-a-03-0-UI.s1 cDNA) (SEQ ID NO:439); AA875047 (TCPZ) (SEQ ID NO:63); AA875059 (rc_AA875059 UI-R-E0-cb-f-04-0-UI.s1 cDNA) (SEQ ID NO:190); AA875129 (rc_AA875129 UI-R-E0-bu-e-01-0-UI.s2 cDNA) (SEQ ID NO:401); H31418 (rc_H31418 EST105434 cDNA) (SEQ ID NO:183); H31665 (rc_H31665 EST105952 cDNA) (SEQ ID NO:158); H32977 (rc_H32977 EST108553 cDNA) (SEQ ID NO:179); H33725 (associated molecule with the SH3 domain of STAM) (SEQ ID NO:228); AA891037 (rc_AA891037 EST194840 cDNA) (SEQ ID NO:398); AA891445 (Skd3) (SEQ ID NO:148); AA891690 (ESTs, Weakly similar to SERC_HUMAN PHOSPHOSERINE AMINOTRANSFERASE [H. sapiens]) (SEQ ID NO:440); AA891717 (USF1) (SEQ ID NO:17); AA891734 (rc_AA891734 EST195537 cDNA) (SEQ ID NO:436); AA891785 (rc_AA891785 EST195588 cDNA) (SEQ ID NO:185); AA891810 (ESTs, Highly similar to GTK1 RAT GLUTATHIONE S-TRANSFERASE, MITOCHONDRIAL [R. norvegicus]) (SEQ ID NO:86); AA891965 (rc_AA891965 EST195768 cDNA) (SEQ ID NO:175); AA892333 (Tuba1) (SEQ ID NO:120); AA892353 (ESTs, Moderately similar to JC5823 NADH dehydrogenase [H. sapiens]) (SEQ ID NO:159); AA892511 (rc_AA892511 EST196314 cDNA) (SEQ ID NO:400); AA892986 (rc_AA892986 EST196789 cDNA) (SEQ ID NO:434); AA893032 (ESTs, Moderately similar to CALX RAT CALNEXIN PRECURSOR [R. norvegicus]) (SEQ ID NO:174); AA893082 (rc_AA893082 EST196885 cDNA) (SEQ ID NO:433); AA893493 (RPL26) (SEQ ID NO:133); AA893607 (rc_AA893607 EST197410 cDNA) (SEQ ID NO:195); AA893708 (KIAA0560) (SEQ ID NO:227); AA893743 (rc_AA893743 EST197546 cDNA) (SEQ ID NO:156); AA894104 (rc_AA894104 EST197907 cDNA) (SEQ ID NO:165); AA799449 (EST, Weakly similar to UBP4 MOUSE UBIQUITIN CARBOXYL-TERMINAL HYDROLASE 4 [M. musculus]) (SEQ ID NO:187); AA799779 (acyl-CoA:dihydroxyacetonephosphate acyltransferase) (SEQ ID NO:221); AA799803 (ESTs, Weakly similar to K1CU RAT KERATIN, TYPE I CYTOSKELETAL 21 [R. norvegicus]) (SEQ ID NO:186); AA799854 (rc_AA799854 EST189351 cDNA) (SEQ ID NO:193); AA799996 (rc_AA799996 EST189493 cDNA) (SEQ ID NO:166); AA800693 (rc_AA800693 EST190190 cDNA) (SEQ ID NO:402); AA800708 (ESTs, Weakly similar to S28312 hypothetical protein F02A9.4-Caenorhabditis elegans [C. elegans]) (SEQ ID NO-176); AA800794 (HT2A) (SEQ ID NO:13); AA800948 (Tuba4) (SEQ ID NO:233); and mammalian homologues thereof.
 42. The set of biomarkers of claim 38, wherein at least one member of the set of biomarkers is an expressed sequence tag (EST).
 43. The set of biomarkers of claim 38, for use in the measurement of age-dependent cognitive decline.
 44. The set of biomarkers of claim 43, wherein the age-dependent cognitive decline is an age-dependent neurodegenerative condition.
 45. The set of biomarkers of claim 44, wherein the age-dependent neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 46. The set of biomarkers of claim 38, for use in the measurement of the degree of the safety or effectiveness of compounds or procedures directed against age-related cognitive decline.
 47. The use of an expressed sequence tag (EST) in an assay for aging in a mammal, wherein the EST is selected from the group consisting of AA963449 (UI-R-E1-gj-e-08-0-UI.s1 cDNA) (SEQ ID NO:153); AA892532 (EST196335 cDNA) (SEQ ID NO:154); AA859626 (UI-R-E0-bs-h-02-0-UI.s1 cDNA) (SEQ ID NO:155); AA893743 (EST197546 cDNA) (SEQ ID NO:156); AI233365 (EST230053 cDNA) (SEQ ID NO:157); H31665 (EST105952 cDNA) (SEQ ID NO:158); AA892353 (ESTs, Moderately similar to JC5823 NADH dehydrogenase) (SEQ ID NO:159); AI639247 (mixed-tissue library cDNA clone rx03939 3) (SEQ ID NO:160); AA858617 (UI-R-E0-bq-b-06-0-UI.s1 cDNA) (SEQ ID NO:161); AI639429 (mixed-tissue library cDNA clone rx00973 3) (SEQ ID NO:162); AA858620 (UI-R-E0-bq-b-09-0-UI.s1 cDNA) (SEQ ID NO:163); AA866291 (UI-R-A0-ac-e-12-0-UI.s3 cDNA) (SEQ ID NO:164); AA894104 (EST197907 cDNA) (SEQ ID NO:165); AA799996 (EST189493 cDNA) (SEQ ID NO:166); AA892805 (EST196608 cDNA) (SEQ ID NO:167); AI639019 (mixed-tissue library cDNA clone rx01107 3) (SEQ ID NO:168); AA799538 (EST189035 cDNA) (SEQ ID NO:169); AI070108 (UI-R-Y0-lu-a-09-0-UI.s1 cDNA) (SEQ ID NO:170); AA866409 (UI-R-E0-ch-a-03-0-UI.s1 cDNA) (SEQ ID NO:171); AA859632 (UI-R-E0-bs-h-08-0-UI.s1 cDNA) (SEQ ID NO:172); AA891651 (EST195454 cDNA) (SEQ ID NO:173); AA893032 (ESTs, Moderately similar to CALX calnexin precursor) (SEQ ID NO:174); AA891965 (EST195768 cDNA) (SEQ ID NO:175); AA800708 (ESTs, Weakly similar to S28312 hypothetical protein F02A9.4); AA964320 (UI-R-C0-gu-e-09-0-UI.s1 cDNA) (SEQ ID NO:177); AA893173 (EST196976 cDNA) (SEQ ID NO:178); H32977 (EST108553 cDNA) (SEQ ID NO:179); AA874887 (UI-R-E0-ci-g-10-0-UI.s1 cDNA) (SEQ ID NO:180); AA850781 (EST193549 cDNA) (SEQ ID NO:181); AI176456 (ESTs, Weakly similar to endothelial actin-binding protein); H31418 (EST105434 cDNA) (SEQ ID NO:183); AA858588 (ESTs, Weakly similar to ODP2 dihydrolipoamide acetyl transferase) (SEQ ID NO:184); AA891785 (EST195588 cDNA) (SEQ ID NO:185); AA799803 (ESTs, Weakly similar to K1CU cytoskeletal keratin (type 1)) (SEQ ID NO:186); AA799449 (EST, Weakly similar to UBP4 ubiquitin carboxyl-terminal hydrolase 4) (SEQ ID NO:187); AA859777 (UI-R-E0-bu-e-10-0-UI.s1 cDNA) (SEQ ID NO:188); AI639532 (mixed-tissue library cDNA clone rx01030 3) (SEQ ID NO:189); AA875059 (UI-R-E0-cb-f-04-0-UI.s1 cDNA) (SEQ ID NO:190); AI012051 (EST206502 cDNA) (SEQ ID NO:191); AA800549 (EST190046 cDNA) (SEQ ID NO:192); AA799854 (EST189351 cDNA) (SEQ ID NO:193); AA892520 (EST196323 cDNA) (SEQ ID NO:194) and mammalian homologues thereof.
 48. The use of claim 47, wherein the assay for aging is a measurement of age-dependent cognitive decline.
 49. The use of claim 48, wherein the age-dependent cognitive decline is an age-dependent neurodegenerative condition.
 50. The use of claim 49, wherein the age-dependent neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 51. The use of claim 47, wherein the assay for aging is a measurement of the degree of the safety or effectiveness of compounds or procedures directed against age-related cognitive decline.
 52. A set of biomarkers for brain aging, comprising mammalian polynucleotides and polypeptides encoded by said polynucleotides: (a) wherein the set of biomarkers comprises at least two members; and (b) wherein the brain expression patterns of the members of the set are significantly altered with aging as determined by a conventional statistical method, with p<0.05.
 53. The set of biomarkers of claim 52, wherein the set contains at least one member selected from the group consisting of AA685974 (EST108806 cDNA) (SEQ ID NO:414); AA799396 (EST188893 cDNA); AA799479 (ESTs, Highly similar to NADH-ubiquinone oxidoreduct.) (SEQ ID NO:295); AA799481 (EST188978 cDNA) (SEQ ID NO:411); AA799529 (EST189026 cDNA) (SEQ ID NO:382); AA799599 (EST189096 cDNA) (SEQ ID NO:380); AA799636 (EST189133 cDNA) (SEQ ID NO:392); AA799680 (EST189177 cDNA) (SEQ ID NO:390); AA799724 (ESTs, Highly similar to DNA-directed RNA polymerase I) (SEQ ID NO:199); AA799773 (EST189270 cDNA) (SEQ ID NO:450); AA799779 (acyl-CoA:dihydroxyacetonephosphate acyltransferase) (SEQ ID NO:221); AA799858 (EST189355 cDNA) (SEQ ID NO:422); AA800026 (EST189523 cDNA) (SEQ ID NO:423); AA800318 (EST189815 cDNA) (SEQ ID NO:432); AA800622 (EST190119 cDNA) (SEQ ID NO:385); AA800693 (EST190190 cDNA) (SEQ ID NO:402); AA800948 (Tuba4) (SEQ ID NO:233); AA801286 (Inositol (myo)-1(or 4)-monophosphatase 1) (SEQ ID NO:265); AA817887 (profilin) (SEQ ID NO:291); AA818025 (CD59 antigen) (SEQ ID NO:85); AA818240 (Nuclear pore complex protein) (SEQ ID NO:312); AA818487 (cyclophilin B) (SEQ ID NO:294); AA819500 (ESTs, Highly similar to AC12_HUMAN 37 kD subunit) (SEQ ID NO:283); AA819708 (Cox7a3) (SEQ ID NO:247); AA848831 (lysophosphatidic acid G-protein-coupled receptor, 2) (SEQ ID NO:328); AA852046 (EST194815 cDNA) (SEQ ID NO:444); AA859545 (ESTs, Weakly similar to hypothetical protein C09H6.3) (SEQ ID NO:425); AA859562 (UI-R-E0-by-b-03-0-UI.s1 cDNA) (SEQ ID NO:403); AA859643 (UI-R-E0-bs-a-08-0-UI.s1 cDNA) (SEQ ID NO:412); AA859645 (attractin) (SEQ ID NO:346); AA859690 (UI-R-E0-bx-e-11-0-UI.s1 cDNA) (SEQ ID NO:396); AA859848 (UI-R-E0-cc-h-10-0-UI.s1 cDNA) (SEQ ID NO:426); AA859954 (Vacuole Membrane Protein 1) (SEQ ID NO:271); AA859980 (T-complex 1) (SEQ ID NO:278); AA860030 (UI-R-E0-bz-e-07-0-UI.s2 cDNA) (SEQ ID NO:404); AA866257 (ESTs) (SEQ ID NO:248); AA866299 (UI-R-A0-ac-f-12-0-UI.s3 cDNA) (SEQ ID NO:449); AA866432 (UI-R-E0-ch-e-06-0-UI.s1 cDNA) (SEQ ID NO:441); AA866477 (UI-R-E0-br-h-03-0-UI.s1 cDNA) (SEQ ID NO:418); AA874830 (UI-R-E0-cg-f-04-0-UI.s1 cDNA) (SEQ ID NO:378); AA874874 (ESTs, Highly similar to alcohol dehydrogenase class III) (SEQ ID NO:258); AA874969 (ESTs, Highly similar to c-Jun leucine zipper interactive) (SEQ ID NO:263); AA874995 (UI-R-E0-cf-d-08-0-UI.s1 cDNA) (SEQ ID NO:393); AA875004 (UI-R-E0-cb-b-07-0-UI.s1 cDNA) (SEQ ID NO:397); AA875019 (UI-R-E0-cb-f-08-0-UI.s1 cDNA) (SEQ ID NO:417); AA875032 (UI-R-E0-cb-h-09-0-UI.s1 cDNA) (SEQ ID NO:379); AA875037 (UI-R-E0-cb-a-03-0-UI.s1 cDNA) (SEQ ID NO:439); AA875129 (UI-R-E0-bu-e-01-0-UI.s2 cDNA) (SEQ ID NO:401); AA875257 (UI-R-E0-cq-d-12-0-UI.s1 cDNA) (SEQ ID NO:413); AA891037 (EST194840 cDNA) (SEQ ID NO:398); AA891041 (un B proto-oncogene) (SEQ ID NO:290); AA891221 (EST195024 cDNA) (SEQ ID NO:387); AA891476 (EST195279 cDNA) (SEQ ID NO:415); AA891537 (EST195340 cDNA) (SEQ ID NO:389); AA891690 (ESTs, Weakly similar to p-serine aminotransferase) (SEQ ID NO:440); AA891727 (EST195530 cDNA) (SEQ ID NO:405); AA891734 (EST195537 cDNA) (SEQ ID NO:436); AA891774 (EST195577 cDNA) (SEQ ID NO:447); AA891810 (EST195613 cDNA) (SEQ ID NO:86); AA891880 (Loc65042) (SEQ ID NO:243); AA891916 (membrane interacting protein of RGS16) (SEQ ID NO:209); AA891944 (EST195747 cDNA) (SEQ ID NO:451); AA891950 (EST195753 cDNA) (SEQ ID NO:416); AA892146 (EST195949 cDNA) (SEQ ID NO:443); AA892298 (EST196101 cDNA) (SEQ ID NO:394); AA892414 (EST196217 cDNA) (SEQ ID NO:409); AA892511 (EST196314 cDNA) (SEQ ID NO:400); AA892520 (EST196323 cDNA) (SEQ ID NO:194); AA892538 (EST196341 cDNA) (SEQ ID NO:395); AA892637 (EST196440 cDNA) (SEQ ID NO:424); AA892775 (Lysozyme) (SEQ ID NO:354); AA892796 (EST196599 cDNA) (SEQ ID NO:406); AA892813 (EST196616 cDNA) (SEQ ID NO:381); AA892986 (EST196789 cDNA) (SEQ ID NO:434); AA893082 (EST196885 cDNA) (SEQ ID NO:433); AA893185 (EST196988 cDNA) (SEQ ID NO:399); AA893199 (EST197002 cDNA) (SEQ ID NO:391); AA893224 (EST197027 cDNA) (SEQ ID NO:428); AA893320 (EST197123 cDNA) (SEQ ID NO:388); AA893584 (EST197387 cDNA) (SEQ ID NO:383); AA893690 (EST197493 cDNA) (SEQ ID NO:386); AA893708 (KIAA0560) (SEQ ID NO:227); AA893717 (EST197520 cDNA) (SEQ ID NO:408); AA893743 (EST197546 cDNA) (SEQ ID NO:156); AA893788 (ESTs, Highly similar to chromobox protein homolog 5) (SEQ ID NO:299); AA893946 (EST197749 cDNA) (SEQ ID NO:429); AA894305 (EST198108 cDNA) (SEQ ID NO:384); AA924925 (ER transmembrane protein Dri 42) (SEQ ID NO:372); AA942685 (cytosolic cysteine dioxygenase 1) (SEQ ID NO:249); AA955306 (ras-related protein rab10) (SEQ ID NO:365); AA955388 (Na⁺K⁺ transporting ATPase 2, beta polypeptide 2) (SEQ ID NO:307); AA957132 (N-acetylglucosaminyltransferase I) (SEQ ID NO:375); AB000778 (Phoshpolipase D gene 1) (SEQ ID NO:357); AB006451 (Tim23) (SEQ ID NO:253); AB008538 (HB2) (SEQ ID NO:324); AB016532 (period homolog 2 (Drosophila)) (SEQ ID NO:259); AF000899 (p58/p45, nucleolin) (SEQ ID NO:286); AF007554 (Mucin1) (SEQ ID NO:266); AF007758 (synuclein, alpha) (SEQ ID NO:260); AF007890 (resection-induced TPI (rs11)) (SEQ ID NO:262); AF008554 (implantation-associated protein (IAG2)) (SEQ ID NO:331); AF013144 (MAP-kinase phosphatase (cpg21)) (SEQ ID NO:281); AF016269 (kallikrein 6 (neurosin, zyme)) (SEQ ID NO:301); AF016296 (neuropilin) (SEQ ID NO:325); AF019974 (Chromogranin B, parathyroid secretory protein) (SEQ ID NO:223); AF020046 (integrin alpha E1, epithelial-associated) (SEQ ID NO:284); AF021935 (Ser-Thr protein kinase) (SEQ ID NO:302); AF023087 (Early growth response 1) (SEQ ID NO:269); AF030050 (replication factor C) (SEQ ID NO:327); AF030088 (RuvB-like protein 1) (SEQ ID NO:280); AF040954 (putative protein phosphatase 1 nuclear targeting subunit) (SEQ ID NO:213); AF051561 (solute carrier family 12, member 2) (SEQ ID NO:322); AF055477 (L-type voltage-dependent Ca²⁺ channel (?1D subunit)) (SEQ ID NO:207); AF074608 (MHC class I antigen (RT1.EC2) gene) (SEQ ID NO:340); AF076183 (cytosolic sorting protein PACS-1a (PACS-1)) (SEQ ID NO:231); AF095927 (protein phosphatase 2C) (SEQ ID NO:246); AI010110 (SH3-domain GRB2-like 1) (SEQ ID NO:273); AI012589 (glutathione S-transferase, pi 2) (SEQ ID NO:356); AI013627 (defender against cell death 1) (SEQ ID NO:208); AI013861 (3-hydroxyisobutyrate dehydrogenase) (SEQ ID NO:342); AI045249 (heat shock 70 kD protein 8) (SEQ ID NO:245); AI102031 (myc box dependent interacting protein 1) (SEQ ID NO:370); AI102299 (Bid3) (SEQ ID NO:320); AI102839 (cerebellar Ca-binding protein, spot 35 protein) (SEQ ID NO:203); AI102868 (EST212157 cDNA) (SEQ ID NO:420); AI104388 (heat shock 27 kD protein 1) (SEQ ID NO:296); AI136891 (zinc finger protein 36, C3H type-like 1) (SEQ ID NO:275); AI168942 (branched chain keto acid dehydrogenase E1) (SEQ ID NO:268); AI169265 (Atp6s1) (SEQ ID NO:219); AI171966 (ESTs, Highly similar to selenide, water dikinase 2) (SEQ ID NO:437); AI175973 (ESTs, Highly similar to NADH dehydrogenase) (SEQ ID NO:198); AI176491 (EST220076 cDNA) (SEQ ID NO:410); AI176595 (Cathepsin L) (SEQ ID NO:351); AI176621 (iron-responsive element-binding protein) (SEQ ID NO:272); AI 77404 (EST221024 cDNA) (SEQ ID NO:431); AI178204 (EST221869 cDNA) (SEQ ID NO:421); AI178921 (Insulin degrading enzyme) (SEQ ID NO:215); AI228548 (ESTs, Highly similar to DKFZp586G0322.1) (SEQ ID NO:316); AI230247 (selenoprotein P, plasma, 1) (SEQ ID NO:300); AI230778 (ESTs, Highly similar to protein-tyrosine sulfotrans. 2) (SEQ ID NO:277); AI230914 (farnesyltransferase beta subunit) (SEQ ID NO:229); AI231807 (ferritin light chain 1) (SEQ ID NO:332); AI232268 (LDL receptor-related protein associated protein 1) (SEQ ID NO:244); AI235344 (geranylgeranyltransferase type I (GGTase-I)) (SEQ ID NO:304); AI237007 (ESTs, Highly similar to flavoprot.-ubiquin. Oxidoreduct.) (SEQ ID NO:376); AI638971 (mixed-tissue library cDNA clone rx04989 3) (SEQ ID NO:446); AI638997 (mixed-tissue library cDNA clone rx05048 3) (SEQ ID NO:430); AI639151 (mixed-tissue library cDNA clone rx02802 3) (SEQ ID NO:438); AI639209 (mixed-tissue library cDNA clone rx00680 3) (SEQ ID NO:419); AI639257 (mixed-tissue library cDNA clone rx01119 3) (SEQ ID NO:448); AI639477 (mixed-tissue library cDNA clone rx02351 3) (SEQ ID NO:407); D00569 (2,4-dienoyl CoA reductase 1, mitochondrial) (SEQ ID NO:311); D10262 (choline kinase) (SEQ ID NO:214); D10699 (ubiquitin carboxy-terminal hydrolase L1) (SEQ ID NO:234); D10854 (aldehyde reductase) (SEQ ID NO:285); D10874 (lysosomal vacuolar proton pump (16 kDa)) (SEQ ID NO:211); D16478 (mitochondrial long-chain enoyl-CoA hydratase) (SEQ ID NO:250); D17309 (delta 4-3-ketosteroid-5-beta-reductase) (SEQ ID NO:364); D28110 (myelin-associated oligodendrocytic basic protein) (SEQ ID NO:309); D28557 (cold shock domain protein A) (SEQ ID NO:313); D29766 (v-crk-associated tyrosine kinase substrate) (SEQ ID NO:202); D37951 (MIBP1 (c-myc intron binding protein 1)) (SEQ ID NO:230); D45247 (proteasome subunit RCX) (SEQ ID NO:212); D45249 (protease (prosome, macropain) 28 subunit, alpha) (SEQ ID NO:338); D78308 (calreticulin) (SEQ ID NO:293); D83948 (adult liver S1-1 protein) (SEQ ID NO:298); D88586 (eosinophil cationic protein) (SEQ ID NO:251); D89340 (dipeptidylpeptidase III) (SEQ ID NO:222); D89730 (Fibulin 3, fibulin-like extracellular matrix protein 1) (SEQ ID NO:344); D90211 (Lysosomal-associated membrane protein 2) (SEQ ID NO:345); E03229 (cytosolic cysteine dioxygenase 1) (SEQ ID NO:252); H33086 (EST108750 cDNA) (SEQ ID NO:427); H33725 (associated molecule with the SH3 domain of STAM) (SEQ ID NO:228); J02752 (acyl-coA oxidase) (SEQ ID NO:368); J02773 (heart fatty acid binding protein) (SEQ ID NO:289); J05022 (peptidylarginine deiminase) (SEQ ID NO:362); J05031 (Isovaleryl Coenzyme A dehydrogenase) (SEQ ID NO:288); J05132 (UDP-glucuronosyltransferase) (SEQ ID NO:330); K02248 (Somatostatin) (SEQ ID NO:270); L00191 (Fibronectin 1) (SEQ ID NO:350); L13202 (RATHFH2 HNF-3/fork-head homolog-2 (HFH-2)) (SEQ ID NO:220); L19998 (sulfotransferase family 1A, phenol-preferring, member 1) (SEQ ID NO:321); L24896 (glutathione peroxidase 4) (SEQ ID NO:318); L25605 (Dynamin 2) (SEQ ID NO:349); L26292 (Kruppel-like factor 4 (gut)) (SEQ ID NO:218); L29573 (neurotransmitter transporter, noradrenalin) (SEQ ID NO:216); L42855 (transcription elongation factor B (SIII) polypeptide 2) (SEQ ID NO:274); M10068 (NADPH-cytochrome P-450 oxidoreductase) (SEQ ID NO:254); M13100 (long interspersed repetitive DNA sequence LINE3) (SEQ ID NO:435); M19936 (Prosaposin-sphingolipid hydrolase activator) (SEQ ID NO:366); M23601 (Monoamine oxidase B) (SEQ ID NO:361); M24104 (synaptobrevin 2) (SEQ ID NO:303); M24104 (Vesicle-associated membrane protein (synaptobrevin 2)) (SEQ ID NO:303); M24852 (Neuron specific protein PEP-19 (Purkinje cell protein 4)) (SEQ ID NO:239); M31174 (thyroid hormone receptor alpha) (SEQ ID NO:264); M36453 (Inhibin, alpha) (SEQ ID NO:206); M55015 (nucleolin) (SEQ ID NO:348); M57276 (Leukocyte antigen (Ox-44)) (SEQ ID NO:367); M58404 (thymosin, beta 10) (SEQ ID NO:282); M80550 (adenylyl cyclase) (SEQ ID NO:204); M83745 (Protein convertase subtilisin/kexin, type I) (SEQ ID NO:226); M89646 (ribosomal protein S24) (SEQ ID NO:371); M91234 (VL30 element) (SEQ ID NO:329); M93273 (somatostatin receptor subtype 2) (SEQ ID NO:197); M93669 (Secretogranin II) (SEQ ID NO:256); M99485 (Myelin oligodendrocyte glycoprotein) (SEQ ID NO:360); S53527 (S100 calcium-binding protein, beta (neural)) (SEQ ID NO:343); S61868 (Ryudocan/syndecan 4) (SEQ ID NO:334); S72594 (tissue inhibitor of metalloproteinase 2) (SEQ ID NO:333); S77492 (Bone morphogenetic protein 3) (SEQ ID NO:276); S77858 (non-muscle myosin alkali light chain) (SEQ ID NO:287); U04738 (Somatostatin receptor subtype 4) (SEQ ID NO:261); U07619 (Coagulation factor III (thromboplastin, tissue factor)) (SEQ ID NO:377); U08259 (Glutamate receptor, N-methyl D-aspartate 2C) (SEQ ID NO:323); U10357 (pyruvate dehydrogenase kinase 2 subunit p45 (PDK2)) (SEQ ID NO:310); U14950 (tumor suppressor homolog (synapse associ. protein)) (SEQ ID NO:306); (immediate early gene transcription factor NGFI-B) (SEQ ID NO:225); U18771 (Ras-related protein Rab-26) (SEQ ID NO:205); U27518 (UDP-glucuronosyltransferase) (SEQ ID NO:279); U28938 (receptor-type protein tyrosine phosphatase D30) (SEQ ID NO:242); U38379 (Gamma-glutamyl hydrolase) (SEQ ID NO:292); U38801 (DNA polymerase beta) (SEQ ID NO:257); U67080 (r-MyT13) (SEQ ID NO:341); U67136 (A kinase (PRKA) anchor protein 5) (SEQ ID NO:336); U67137 (guanylate kinase associated protein) (SEQ ID NO:339); U72620 (Lot1) (SEQ ID NO:224); U75405 (procollagen, type I, alpha 1) (SEQ ID NO:217); U75917 (clathrin-associated protein 17) (SEQ ID NO:240); U77777 (interleukin 18) (SEQ ID NO:319); U78517 (cAMP-regulated guanine nucleotide exchange factor II) (SEQ ID NO:369); U89905 (alpha-methylacyl-CoA racemase) (SEQ ID NO:238); V01244 (Prolactin) (SEQ ID NO:317); X02904 (glutathione S-transferase P subunit) (SEQ ID NO:355); X05472 (2.4 kb repeat DNA right terminal region) (SEQ ID NO:442); X06769 (FBJ v-fos oncogene homolog) (SEQ ID NO:200); X06916 (S100 calcium-binding protein A4) (SEQ ID NO:335); X13905 (ras-related rab1B protein) (SEQ ID NO:315); X14323 (Fc receptor, IgG, alpha chain transporter) (SEQ ID NO:352); X16933 (RNA binding protein p45AUF1) (SEQ ID NO:373); X53427 (glycogen synthase kinase 3 alpha (EC 2.7.1.37)) (SEQ ID NO:241); X53504 (ribosomal protein L12) (SEQ ID NO:139); X54467 (cathepsin D) (SEQ ID NO:314); X55153 (ribosomal protein P2) (SEQ ID NO:347); X57281 (Glycine receptor alpha 2 subunit) (SEQ ID NO:235); X58294 (carbonic anhydrase 2) (SEQ ID NO:359); X59737 (ubiquitous mitochondrial creatine kinase) (SEQ ID NO:297); X60212 (ASI homolog of bacterial ribosomal subunit protein L22) (SEQ ID NO:305); X62950 (pBUS30 with repetitive elements) (SEQ ID NO:326); X67805 (Synaptonemal complex protein 1) (SEQ ID NO:210); X72757 (cox VIa gene (liver)) (SEQ ID NO:374); X74226 (LL5 protein) (SEQ ID NO:353); X76489 (CD9 cell surface glycoprotein) (SEQ ID NO:308); X76985 (latexin) (SEQ ID NO:236); X82445 (nuclear distribution gene C homolog (Aspergillus)) (SEQ ID NO:232); X84039 (lumican) (SEQ ID NO:237); X89696 (TPCR06 protein) (SEQ ID NO:201); X97443 (integral membrane protein Tmp21-I (p23)) (SEQ ID NO:358); X98399 (solute carrier family 14, member 1) (SEQ ID NO:267); Y17295 (thiol-specific antioxidant protein (1-Cys peroxiredoxin)) (SEQ ID NO:337); Z48225 (protein synthesis initiation factor eIF-2B delta subunit) (SEQ ID NO:255); Z49858 (plasmolipin) (SEQ ID NO:363) and mammalian homologues.
 54. The set of biomarkers of claim 52, wherein at least one member of the set of biomarkers is an expressed sequence tag (EST).
 55. The set of biomarkers of claim 52, for use in the measurement of age-dependent cognitive decline.
 56. The set of biomarkers of claim 55, wherein the age-dependent cognitive decline is an age-dependent neurodegenerative condition.
 57. The set of biomarkers of claim 56, wherein the age-dependent neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 58. The set of biomarkers of claim 52, for use in the measurement of the degree of the safety or effectiveness of compounds or procedures directed against age-related cognitive decline.
 59. The use of a biomarker for brain aging in the treatment of cognitive decline in aging in a mammal, (a) wherein the biomarker is a polynucleotide or a polypeptide encoded by said polynucleotide, selected from the group consisting of: (1) a biomarker selected from the set of biomarkers of claim 23; (2) a biomarker selected from the set of biomarkers of claim 38; (3) a biomarker selected from the set of expressed sequence tags (EST) of claim 47; and (4) a biomarker identified by the method of claim 1; and (b) wherein the treatment is targeted to a polynucleotide corresponding to the biomarker or to a polypeptide encoded by said polynucleotide.
 60. The use of claim 59, wherein at least one member of the set of biomarkers is an expressed sequence tag (EST).
 61. The use of claim 59, wherein the cognitive decline in aging is an age-related neurodegenerative condition.
 62. The use of claim 61, wherein the age-related neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 63. The use of a biomarker for brain aging, in identification of a medicament for the treatment of cognitive decline in aging in a mammal, (a) wherein the biomarker is a polynucleotide or a polypeptide encoded by said polynucleotide, selected from the group consisting of: (1) a biomarker selected from the set of biomarkers of claim 23; (2) a biomarker selected from the set of biomarkers of claim 38; (3) a biomarker selected from the set of expressed sequence tags (EST) of claim 47; and (4) a biomarker identified by the method of claim 1; and (b) wherein the treatment is targeted to a polynucleotide corresponding to the biomarker or to a polypeptide encoded by said polynucleotide.
 64. The use of claim 63 wherein at least one member of the set of biomarkers is an expressed sequence tag (EST).
 65. The use of claim 63, wherein the cognitive decline in aging is an age-related neurodegenerative condition.
 66. The use of claim 65, wherein the age-related neurodegenerative condition is Alzheimer's disease or Parkinson's disease.
 67. A medicament, device or procedure for the treatment of cognitive decline in aging in a mammal, (a) wherein the medicament is identified by the use of a biomarker, (b) wherein the biomarker is a polynucleotide or a polypeptide encoded by said polynucleotide, selected from the group consisting of: (1) a biomarker selected from the set of biomarkers of claim 23; (2) a biomarker selected from the set of biomarkers of claim 38; (3) a biomarker selected from the set of expressed sequence tags (EST) of claim 47; and (4) a biomarker identified by the method of claim 1; and (c) wherein the treatment is targeted to a polynucleotide corresponding to the biomarker or to a polypeptide encoded by said polynucleotide.
 68. The medicament, device or procedure of claim 67, wherein the cognitive decline in aging an age-related neurodegenerative condition.
 69. The medicament, device or procedure of claim 67, wherein the age-related neurodegenerative condition is Alzheimer's disease or Parkinson's disease. 